is there an ebuild for a modem server of some kind?

[Twister]

I'm seaching for an application that can host modems (ISDN or PSTN) on a network.
Say like 5 PSTN modems and 5 ISDN modems with 5 clients.
So these clients can connect to the host and request a PSTN or ISDN modem (maybe on a different port, whatever) and the host gives them the first available modem of that type.

Something like that

cheers