DSS V6 replication via LAN and WAN together

Hi,

I had got 3 site and total 7 DSS V6 server. 2 in site one with automatic failover, another 2 in another site with automatic failover. I had got 3 spare DSS in another location and i had VPN connection between each location. I want to make faulttolerance in such a way that volume is replacted to 1 each DSS at the remote site 3. So can you please let me know is that possible. So that 1st autofailover will work and incase both of that fails then we have got the remote replication to work out with.