AP Invoice matching against receipt

Hi All

I dont know if its a built in function or something i have to design on my
own so i thought i will post to this great group so i will know where to

I'm currently looking to enforce PO receipt and AP invoice matching.

So for all suppliers except a select few that are service related i want to
enforce that a Invoice can only be entered against a receipt and if not or
the amount doesnt match then it has to be approved or flagged for review by
our CFO.
For the suppliers that dont have PO's like service etc. we should be able to
enter regular invoices without matching to a receipt.

Any help on this topic would be appreciated

Ephraim Feldman

[Non-text portions of this message have been removed]