Routing to internet domain via notes rpc

I have 2 domino domains.the first one recieves mail from the internet and sends mailto the second domain via nrpc using a connection record with out any problem.

The issue is how do I route mail addressed to the users internet address(not the notes address)between the 2 domains via nrpc and not using smtp.

I have sent up a connection document between the 2 domains - this works fine for notes.

I have a foreign smtp domain document - but this is smtp.

how do domino know that internet domain abc.company.con is linked to the second domino domain.

Thanks