Best process within collections for handling outsourcing individual invoices to 3rdparty

Summary:

We have a process of outsourcing individual invoices to outside collector parties. Expectation is when invoices are flagged or outsourced - they disappear from collector's queue - and when payment is received - it gets applied to invoices and reduce their balance. The commission that the third party keeps can remain as open balance on invoice and be written off.

Is there any process within collection to handle them - at a transaction level.