PPR: Custom validation other than user defined validation

Summary:

PPR: Custom validation other than user-defined validation. We are upgrading from Peoplesoft where we had many validations on Invoices and payment records before running pay cycles to payments. Some of these can be utilized in PPR validations from user defined validations but many are not. We are looking for suggestions to have a custom validation hook kind of a feature in Cloud to have this in place (this was available in EBS R12).

2 Broader areas we are thinking of are as below:

1) Can we build custom validation in payment template BIP template and raise error if they fail? This is for the cases where oracle out of box validation doesn't allow to build validations.