Power vs AltPower

[Pyrates]

There are some bosses that use special abilities based on some sort of power, but not all of them use the AltPower. For example, omnotron council and the conclave use the regular power bar for this, but Onyxia (from the nefarian encounter in bwd) uses the altpower bar.

Is there any good way to show all of this in one bar? I do have an altpower bar, that works nicely for onyxia. Could I somehow use this to show power for omnotron and conclave? I think just something along the lines of "self.Power = self.AltPowerBar" could do the trick, but I'm unclear on when to make this change and when to revert it.

Did anybody bother with this particular problem and solve it, or does anyone have an idea what to do about it? I'd like to avoid making 2 bars for power and altpower separately, because it's always only just 1 being relevant. Thanks for any pointers