2 Servers 3 VPN’s

I Have A Server / VPN Problem.

We Current Have SBS2003, Our remote staff Can VPN in via SBS2003 Internal VPN. Quick and easy for the Sales guys.

The problem is We are opening a new office that will operate independantly with the same system.

I need to find some way to Map a Drive of each server to a Drive on the Other server for the exchange of common data.

Basically
VPN 1 Local Server A ( Site A Remote Users)
VPN 2 Local Server B ( Site B Remote Users)

VPN 3 Server A to Server B ( Server to Server Mapped Drives)

VPN 3 is my problem