Yes, you can add other vpn connections without having to add interfaces. What you do is to add additional config statements on the crypto map using differenct seq numbers, but the same map name, for each connection. Note with pix 6.2 and earlier code when you add new cry map seq numbers, make sure that the acl that defines the interesting traffic and the peer key are defined first, and then add the cry map statements relating to those before you add the rest. I am not sure about pix 6.3 code, but earlier code versions would block all traffic (vpn as well as non-vpn) until the new cry map seq statements had a match-address and a match-peer defined.
