Nicely documented study, a good starting point.
N_OP > Threshold
For every N OP: Kill N-1 OPs
Increase the weight of remaining OP by N
Let 1 OP of higher weight stand in for N of them
The rescale is done in Geant4 StackingAction which means OPsare already created and only the propagation is suppressed. Further work can move the compression into scintillation process to suppress the creation of them.