I have 3 PIX 515E running 7.2(3)
PIX1 can see PIX2 inside networks
PIX2 can see PIX1 and PIX3 inside networks
PIX3 can see PIX2 inside networks
(I was not here for this numbering)
All running IPSec VPN between them. My guess is once this is figured out I should be able to figure out how to also connect Cisco VPN 3 clients to PIX2 to see all networks if not able to connect Cisco VPN 3 clients to PIX1 and PIX3 and see all networks as well.