Conditional Formatting Based on Comparison Between Multiple Cells

I would like to use a conditional format that will find a match for each "Account 1" number somewhere in the "Account 2" column. Then once a match of Account numbers is found, highlight each "Phase 1" letter associated with each "Account 1" number that does not match each "Phase 2" letter associated with each "Account 2" number. In this example, the cells B3, B6, & B8 should be highlighted (Phase 1 & Phase 2 don't match for Account 5002, nor Account 5005, nor Account 5007.

Thanks for the help!