Router Selection for Multiple Subnet NATing

I currently have a router (Linksys RV042) that only allows port forwarding to 1 subnet.  I am attempting to allow an H.323 device on the Internet to connect to an H.323 device behind the firewall and then further down the network across another VPN span to another subnet.  Presently I can route traffic fine in terms of getting out, however obviously with H.323 udp packets I have some additional problems because while the tcp traffic can negotiate, the udp packets are dropped since there's no apparent route back even when masquerading the public IP from the internal H.323 device since the RV042 has no way of understanding the route back down the inside device when traffic is inbound.

Here's a quick diagram of the network (presently I don't have the two VPNs teamed, as that's another issue I'm tackling right now, but that's really a different matter).

You can see from this that my immediate need is to connect the "Office 1" "H.323 1" device to the "Remote Site / Node 2" "H.323 2" device.  That is what that red arrow between the two indicates.

So essentially I need to understand what router would be optimal in this situation.  Cisco / Linksys is telling me that they don't think they have a small business class router that will handle it and that I'll probably have to jump up to enterprise class.  It seems that perhaps DD-WRT or RouterOS (MikroTik) could handle this or perhaps another solution.  Can someone please recommend a router or appropriate OS that would be ideal for this and support a bunch of video traffic in this regard?

Another important feature is that I must be able to assign public IPs to devices down inside the network on the other subnets as well.  Each of these devices on the internal network is to offer publicly accessible services from various kinds of devices.

So a recommendation for an appropriate router would be superb.

A bonus is that I must be able to team the two VPNs, which I could essentially use to create perhaps one homogenous subnet, which would also work, but I'm unclear about the best option for teaming VPNs at the moment.