how we can automate Withholding Tax starting from Procurement to AP

Hi All

Would you please confirm, how we can automate Withholding Tax starting from Procurement to AP.

Example:
We create PO with 2 lines for 2 different service each one has different with holding tax "5% and 10%" , how we can record those rates into PO lines and then match it with invoice in AP module

Please lets us know what is the functionality or process

Thanks

N