Bob,

Thanks for the info!

If you have a Home Depot near by, they probably have the DPST

We have a couple of HD's and a Lowes nearby. I'll have a look next time I'm
there. I've never had a need for them before, so I've probably looked over
them and didn't know it.

The DPST solution will only work IF the neutral to the fan comes from
the switch box & can be safely broken there.

Yep, the power comes into the 3-gang switch box, then separate cables run
to the fans and lights. It'll be no problem switching to the DPST switch.

I'll have to wait and see if changing the switch will prevent the GFCI from
tripping when the fan is turned off, but it's a relatively simple and
inexpensive thing to try. Thanks for the tip.

Anthony