I figured it out by using the Rectangle but now how to make that indicator see the yes/no column. My expression for the indicator corresponding to yes/no/null is:

=Fields!Passed.Value*100

with red: 50 to 100, yellow: 41 to 49, and green: 0 to 40. Somehow this works but now I just want one indicator for a group if an X is present or if there is an exclamation if there are any nulls, else everything should be a yes and therefore a checkmark. Is this an if/else? If so, can anyone point me in the right direction on how to write it. Thanks!