You're referring to Matrix ITA although you can no longer plug in airports from different countries as a starting point so you'll have to do that in a more manual fashion. I would imagine that you'll have other problems with an ex-EU approach too in that you'll need to position there and back and take time out of work to do that. Perhaps that won't be a problem for you? You'll also possibly run into flexibility problems so be sure to check the fare rules of the Concur fare quote. If you choose to pay for an alternative fare that has less flexibility and then need to change your plans you may find yourself on the hook for those costs too.

It's probably a good idea to talk with your colleagues to form of a view of what is considered acceptable practice.