PRO-SITES - PAYPAL IPN - Multiple IPN urls?


I've had several problems with pro sites not working and creating the website when payment is successful etc. I came to the conclusion that it was due to my IPN not being setup, but I am already using the IPN for another site / url that accepts payments.

Do you have any suggestions on setting up IPN for my pro sites site, as well as my other sites that use ipn.

I found this here:

Could this work? If this was used, what would be the 'if' conditions used to successfully apply the ipn for the pro site IPN, else I would do the other IPN.

Any ideas/suggestions appreciated.