I hope the subject makes sense...

Basically, our UK office has an EXTERNAL GW SYSTEM for our US office. This enables us to send/receive emails to them as if they were part of the same mails system, amongst other things.
They connect because a VPN link exists between us and them.

But, the VPN link is down, so all Emails between us and them queue up, and won't get delivered.

My question is how can I get the mails to be delivered, if the VPN link is down? Can I set any alternative route or anything? Both Internet connections are up, both GWIA's run fine, but it wants to send/retrieve via the MTA's, so can I set anything up in the mean time?

Thanks in advance, Alan