[exim] control relay domains

hello ppl,

I'm using Debian Testing with Exim 4.34-4 and I'm doing relay for some virtual domains that I answer for DNS too.
now, I need create some emails account for dial-up connections (dynamic IPs) outside my network.
How can I open my server for relay just for that users?


--
Djalma Fadel Junior
Diretor Técnico
Ferasoft Corporation Ltda
+55 (19) 3542-3490
dfadel@???