indengr
A correctly configured sme in server gateway mode supports multiple VPN connections from different hosts.
Interconnecting equipment (routers etc) need to correctly support WINS.
You can only make one VPN connection from a host, meaning if you want 4 workstations at a remote location (same host) to connect via VPN to another sme server, it won't work.
You can make 4 (or many more) VPN connections from different locations (different hosts) quite OK.
The speed of the connection will greatly depend on the speed of the Internet connection at the main VPN server.
VPN connections are usually much slower, and not suited to running programs etc, but OK for uploading/downloading files, or opening smallish files across the connection.
If you want speed use a different technique.
If you want multiple VPN connections from workstations at the same location (host), you need to use a VPN tunnel like Open VPN or similar.
See
http://wiki.contribs.org/VPN_practical_tips