Clustering Problems

I have a Netgear CG3000DCR with a block of five static IP addresses, two of the IPs are used for a firewall and a server, and I am trying to use the other three for a second VPN cluster that uses three IP addresses.  One for each node and a third floating virtual IP.

When this is configured devices behind the cluster are seeeing a ~40% packet loss on pings.  I read on another forum that the Netgear device might have issues with the virtual IP and the gratuitous ARP, so I am wondering if any other Comcast model might support this?

The other firewall and server are having no problems, so this is not a Comcast service issue, but a modem hardware isue.