Hello,
I'll be happy to talk to you more about this and what hardware do you have in place, topology and so on... The big warring sign I see here is it's 2015 and you're vulnerable to mac address spoofing which tells me you've been cutting corners building this network for a long time now which may not be that easy to fix now. While we can build static mac tables on the boxes and so on you should really use encryption on those links. We can talk about it in more detail once you explain your exact use case scenario.