Purchasing Document - ATP - inclusion/exclusion criteria

Dear All.

We're looking for ways to include some types of PO's in the ATP calculation for the receiving plant, and also exclude some other types of PO's in the calculation.

ECC standard ATP configuration (OVZ9) just let's us include or exclude, but not specify a more detailed set of rules.

We also looked at 'EXIT_SAPLATPC_001', but this looks to specify control parameters on the ATP check but not the calculation.

Wanted to see if anyone had any other thoughts on ways to do this, possibly the PO Type, Item Category on the PO, Purchasing Group, etc....

Or other userexit?

Thanks.