Virtual domain

Hello,

I need to install a sme server 5.5 as a mail server.

The mail server should manage two internet domain, let's say. Unfortunetly, I will use MultiDrop to retreive the mail of the two domain (the only mode available here).

Is "virtual domain" good to say my server to manage two mail domain ?
Is it compatible with Multi Drop ?

Last problem, I've got two ISP (one for each domain). Can we tune the server to retreive the mail from both or should i use only one ISP managing my two domain.

Thanks,

benja