Conditions for dragging two possible items to 2 different areas

I may be pushing the limit of Storyline here - or of my brain!  LOL

I have 6 circles, 2 each of red, green, yellow. The student has to drag a circle to a bucket (the target). I have 6 buckets. Since I know the answers, of course, I can easily drag G1 (green circle 1) to B1 (bucket 1) and G2 to B2 and so on. And the circles are DISABLED on the drop, so they can no longer be moved.

The answers that are correct are given right away - with a correct drop. A field pops up saying correct.

The problem is: Nothing keeps the student from dropping G1 onto B1, and then G2 also onto B1. I have tried using and checking states, variables, true/false, number increase, and so on. I'm sure I'm missing something quite simple.

Let's say the correct answers are:

G1 or G2 -> B1

G1 or G2->B2

Y1 or Y2 -> B3

Y1 or Y2 > B4

R1 or R2 > B5

R1 or R > B6