Including conditions of formatting inside an if statement

In the dilemma above, I have it set up so that when a student checks out of their room, they get an "x" next to their name.  Then when both students are individually marked as checked out of their room, the large "X" appears to show that room is now empty.  When a room is marked with a big "X", this then causes the room number and both occupants' names to highlight green via conditional formatting.

My question is:  Is there a way to compile a list of only room numbers in the smaller chart to the right, but only when that number is highlighted green?  So something along the lines of =IF(A1 is highlighted green, then display that room number)