I am looking for advice on the best way to handle the following situation. We have instances, where we invoice our members for various services and in turn their Prof Corps, Employers, Business Managers are the one's who actually pay the invoice on their behalf. For example we could have 5 members, who belong to same Prof Corp, we bill them on a monthly basis and they pay via PAD.

We want to be able to link the payment to the individual member, but we also want to make sure receipts go to their Prof Corp, business office, etc. Is there a way to track in A/R who was invoiced and who paid?

Take a look at National Accounts by Dakota Softrak - http://www.dakotasoftware.com/national.html . It does just this.

It is very very easy to install and set up.