Can PIX 501 establish site-to-site VPN with dynamic IP at both ends?

I need some guidance and hope someone here can help. I have a network with 8 physical locations. Currently the main office has a static IP address and a Cisco 506e PIX that is connected to all other locations’ Cisco 501 PIX via VPN. This gives everyone access to the main server and files. I would like to establish VPN connectivity from all locations to the others to get a full mesh network and allow employees working temporarily at any location access to the server at their native location. Is this possible with dynamic external IPs? All locations are within the network and are assigned non-routable local addresses so maybe there’s a way to use DNS to estalish the VPNs. I’m fairly new at PIX configs and would appreciate any input. THANKS.