Something I did the other day in one of my games.
The PCs found an item called a backfire mantle. It gives a +1 to Reflex saves vs. your allies area spells.
At first I couldn't figure out how to work it in. So what I did was, I added an effect to the tracker (and set it to GM visible only) that gave a +1 Reflex saves. Then I drug the Target button from the effect to all the casters in the group (I had to make one for each caster target).

But now if his own ally hits him with a Reflex save, he gets a bonus to just that effect.

If I took the long way around, be sure to let me know. But it worked for me. And maybe it'll help somebody else.