How could I get if two colliders in different positions have been triggered by two different objects?

Hello there! :)

I wonder how could I get the collider A (Which is a small box on the left) is triggered by the object A (Which is a small blue sphere) and the collider B (Which is a small box on the right) is triggered by the object B (Which is a small red sphere)? :)

The point is that something happens when blue touches left-box and red touches right-box and no the other way around. I'd like also to do something when blue touches left and red touches a yellow triangle in top-right.

Thanks in advice!