Windows 7: Multiple Site to Site VPN

20+ computers, all running windows 7 32 bit (pro or higher).
2 site to site vpn connecting to 4 external websites

Some computers will connect to sites 1,2, and 3, but not 4.
Others will connect to site 4, but not 1, 2, or 3.

Since all 4 sites can connect, we can eliminate any VPN issues.
Regardless of were on the network a computer is located, the connection for that machine is the same, so it is a computer issue not a network issue.

I have tried using IE9, Firefox, and Chrome, results are the same, not a browser issue.

Firewall on or off, results are the same, not a windows firewall issue.

Double checked, network adapter settings (static network) all settings are Identical.

I have double checked the advanced settings in the internet options, they are identical in all machines.

I have checked and eliminated all possibilities that I can think of.
Does anyone have any ideas what might be causing this?