Account Determination of GR/IR Account while MM postings

Hello Experts,

The clients wants to modify the logic used for account determination while posting to GR/IR Account. The requirement is that the system should check the Recon account for the vendor. There are 4 recon accounts. And in WRX also there are 4 General Modifiers in OBYC and 4 GLs.

The requirement is that based on the recon account, the system should check for combination of general modifier and the GL account mentioned in obyc, and then post to a different account as specified.

And this should be triggered from any transaction which would post to these GLs.

Can someone suggest me which is the user exit/enhancement where I can create this logic?

Thanks and Regards,

Sameer Joshi