Hello ChrisOBrooks,
The best way I can think of to set this up would be to set up your own custom collision channels. If you do this, you can set up your list of physics actors to belong to that channel. You can then have the trigger box only overlap objects of that channel and ignore everything else.
You can set up these custom collision channels under Edit > Project Settings > Collision. You would be looking to use Object channels.
Hope this helps!