Why can't I put a box trigger in the component section of my blueprint?

I know I can make a special box trigger blueprint which essentially does the same, but what if I want a blueprint that has a mesh at the root, but a box trigger on each side of the mesh?

Why can’t I add certain components to an actor blueprint? what are the rules to this? because right now with my current understanding it seems pretty arbitrary.

Hi!

You can create blueprint with mesh and add several Shape component. If you add events for all this shapes, you get several custom trigger volumes.
If you need comunicate your blueprint with Level Blueprint or other blueprints in project, read this docs

https://docs.unrealengine.com/latest/INT/Engine/Blueprints/UserGuide/BlueprintComms/index.html

AH! So you can just add a box component and turn it into a trigger by registering the right events!? thank you SO MUCH this has REALLY solved a key issue for me! thank you thank you thank you thank you thank you!!!