workflow for MIGO process

Hi Experts,

I have a requirement as below. an Inbound delivery comes from Airba to ECC. user goes to MIGO and creates a GR based on inbound delivery. As far as my knowledge goes, after the post, material document and accounting documents are created in the system. can we trigger a workflow immediately after the post and stops the material document and accounting document creation. once the final approval is done, then do the actual POST? Basically user wants to have some approval to happen before the actual GR is posted in the system. is there a better way, like first hold the MIGO trigger approval and at final approval post the GR

thanks