How to round the requirement quqntity to single SU when pick it from Bulk

Hi sirs;

  i meet an issue when i use Bulk storage type , when i pick one quantity i want the quantity will be round up to one single SU in the

storage type bulk,  I set the Overdeliveries required in WM movement type , but what i get is the whole quantity in the bin will be picked when i create TO. but i just want the whole SU not all SUs in the same bin.