Replace stacked 3-way switched on separate panel circuit
All duplex devices, receptacles, switches, combos, etc, have a small tab between the hot (and neutral if present) terminals. You certainly can take a duplex/stack/dual 3-way switch and isolate the two switches on the device. Just break the small tab between the gold screws.

See the small tab with the slot between the screws? 



A 3-way/3-way version of this switch will have four black screws on the opposite side.