Periodic Bills for Contingency Collection Matter

SUGGESTED

I have set up a matter on a contingency basis.  It is a collection matter and we are to receive 1/3 of any amounts collected.  We are collecting money pursuant to a wage deduction order, so we receive payments periodically.  The firm is to receive 1/3 of the amount collected and the client is to receive the remaining 2/3.  How do I run bills for this type of situation and show the deposits and payments in the client fund?