Need expression for text marked with multiple conditions

In FM 8 (Windows XP), how can you show a specific condition (A) when it is the only condition applied to a block of text? I have some text that has two conditions applied (A+B), and I want that text hidden.

I've tried different approaches in the Build Expression dialog box, but get an "Invalid expression" message no matter what I try. What I need Frame to do is "Show A NOT A+B."

We're going to newest version of FM later in the year, so if this cannot be done in FM 8, can it be done in the current version of FM?

Thank you for your help.