Prosites, multiple IPN with Paypal.

Ok, I’m already using paypal else where, and the IPN is already used.

Actually, I need to have multiple pro-sites gateways.

So if for example, I’ve got (For all cat lovers to buy blogs) and also (For all dog lovers to buy blogs) how would I setup more than one IPN?

I was looking at is that a logical/reasonable way of doing things?