diff --git a/Detectors/Upgrades/ALICE3/IOTOF/simulation/include/IOTOFSimulation/Chip.h b/Detectors/Upgrades/ALICE3/IOTOF/simulation/include/IOTOFSimulation/Chip.h
index 1849907d6e071..a692fa2a5b8bc 100644
--- a/Detectors/Upgrades/ALICE3/IOTOF/simulation/include/IOTOFSimulation/Chip.h
+++ b/Detectors/Upgrades/ALICE3/IOTOF/simulation/include/IOTOFSimulation/Chip.h
@@ -78,7 +78,10 @@ class Chip
 
   /// Resize the vector of tdc states
   void resizeTDCStates(int const size) { mTDCStates.resize(size); }
-  std::vector<std::array<double, 2>>& getTDCStates() { return mTDCStates; }
+  std::vector<std::array<double, 4>>& getTDCStates() { return mTDCStates; }
+
+  void resizeMaskStates(int const size) { mMaskStates.resize(size); }
+  std::vector<double>& getMaskStates() { return mMaskStates; }
 
   void addDigit(UShort_t row, UShort_t col, Int_t charge, double time, ULong64_t bc, Int_t tdc, o2::MCCompLabel label);
 
@@ -86,7 +89,8 @@ class Chip
   Int_t mChipIndex = -1;                                ///< Chip ID
   bool mDisabled = false;                               ///< Flag to indicate if the chip is disabled (e.g. due to dead channels)
   std::map<DigitKey, o2::iotof::LabeledDigit> mDigits;  ///< Map of fired digits, possibly in multiple frames
-  std::vector<std::array<double, 2>> mTDCStates;        ///< Vector of the last times the TDC pairs went busy
+  std::vector<std::array<double, 4>> mTDCStates;        ///< Vector of the last times the TDC pairs went busy
+  std::vector<double> mMaskStates;                      ///< Vector of the last time the RO column was masked
 
   ClassDefNV(Chip, 1);
 };
diff --git a/Detectors/Upgrades/ALICE3/IOTOF/simulation/include/IOTOFSimulation/DPLDigitizerParam.h b/Detectors/Upgrades/ALICE3/IOTOF/simulation/include/IOTOFSimulation/DPLDigitizerParam.h
index 48c873d86dc2f..520ac14265619 100644
--- a/Detectors/Upgrades/ALICE3/IOTOF/simulation/include/IOTOFSimulation/DPLDigitizerParam.h
+++ b/Detectors/Upgrades/ALICE3/IOTOF/simulation/include/IOTOFSimulation/DPLDigitizerParam.h
@@ -47,7 +47,8 @@ struct DPLDigitizerParam : public o2::conf::ConfigurableParamHelper<DPLDigitizer
   int responseMatrixSize = 1;             ///< size of the response matrix (odd number)
 
   int nColsPerGroup = 4;      ///< number of pixel columns grouped into a readout column
-  double tdcBusyTime = 3000.; ///< tdc pair bsuy time (default 3 us)
+  double tdcBusyTime = 3300.; ///< tdc pair bsuy time (default 3.3 us)
+  double maskWindow = 100.;   ///< RO column masking time (default 100 ns)
 
   std::string noiseFilePath{}; ///< optional noise masks file path. FIXME to be removed once switch to CCDBFetcher
 
diff --git a/Detectors/Upgrades/ALICE3/IOTOF/simulation/src/Digitizer.cxx b/Detectors/Upgrades/ALICE3/IOTOF/simulation/src/Digitizer.cxx
index a7adbb9b2485d..74ea308a7126f 100644
--- a/Detectors/Upgrades/ALICE3/IOTOF/simulation/src/Digitizer.cxx
+++ b/Detectors/Upgrades/ALICE3/IOTOF/simulation/src/Digitizer.cxx
@@ -20,6 +20,7 @@
 #include "IOTOFSimulation/DPLDigitizerParam.h"
 #include "DetectorsRaw/HBFUtils.h"
 #include "CCDB/BasicCCDBManager.h"
+#include "CommonConstants/MathConstants.h"
 
 #include <TCollection.h>
 #include <TFile.h>
@@ -63,8 +64,14 @@ void Digitizer::init()
     // initialize the vector of TDC states
     mChips[i].resizeTDCStates(nReadOutCols);
     for (auto& tdcStates : mChips[i].getTDCStates()) {
-      tdcStates[0] = -999.f;
-      tdcStates[1] = -999.f;
+      for (int iT = 0; iT < 4; ++iT) {
+        tdcStates[iT] = -o2::constants::math::VeryBig;
+      }
+    }
+    // initialize the vector of mask states
+    mChips[i].resizeMaskStates(nReadOutCols);
+    for (auto& maskStates: mChips[i].getMaskStates()) {
+      maskStates = -o2::constants::math::VeryBig;
     }
   }
 
@@ -497,6 +504,7 @@ void Digitizer::fillOutputContainer()
 
     auto& chipDigits = chip.getDigits();
     auto& tdcStates = chip.getTDCStates();
+    auto& maskStates = chip.getMaskStates();
 
     for (const auto& [key, digit] : chipDigits) {
 
@@ -506,15 +514,26 @@ void Digitizer::fillOutputContainer()
 
       const int colInGroup = digit.getColumn() / digitizerParams.nColsPerGroup;
       const double digitTime = digit.getTime();
-      if (digitTime - tdcStates[colInGroup][0] < digitizerParams.tdcBusyTime && digitTime - tdcStates[colInGroup][1] < digitizerParams.tdcBusyTime) {
-        // TODO: improve labels treatment if multiple hits cross the same pixel during
-        continue; // both tdc pairs are busy
-      } else if (digitTime - tdcStates[colInGroup][0] > digitizerParams.tdcBusyTime) {
-        tdcStates[colInGroup][0] = digitTime;
-      } else if (digitTime - tdcStates[colInGroup][1] > digitizerParams.tdcBusyTime) {
-        tdcStates[colInGroup][1] = digitTime;
+
+      if (digitTime - maskStates[colInGroup] < digitizerParams.maskWindow) {
+        continue; // the RO column is still masked
       }
 
+      int available = -1;
+      for (int iT{0}; iT < 4; ++iT) {
+        if (digitTime - tdcStates[colInGroup][iT] > digitizerParams.tdcBusyTime) {
+          available = iT;
+          break;
+        }
+      }
+
+      if (available == -1) {
+        continue; // all tdc pairs are busy
+      }
+
+      tdcStates[colInGroup][available] = digitTime;
+      maskStates[colInGroup] = digitTime;
+
       int digitID = mDigits->size();
       mDigits->emplace_back(digit.getChipIndex(), digit.getRow(), digit.getColumn(), digit.getCharge(), digit.getTime(), digit.getBc(), digit.getTdc());
       if (mMCLabels) {