Conditional Formatting Formula Help

Hi everyone, i need some help on a formula in conditional formatting that has multiple criteria's.  So attached is the spreadsheet ill be talking about.  Between the A's and B's, I need at least 4 but a minimum of 1 "A".  so if there is 1 "A" but 2 or less "B's" I want the B to highlight blue, if there are 4 "A's", "B" does not need to be highlighted. if there are 2 A's and 2 B's, B does not need to be highlighted.  I hope this makes sense and hopefully even possible to do.

Thank you for your time and help