You could replace them with z-wave switches. The switches by default would control the respective lights they're wired to, but you could use scenes to control the other switch. For example, 2x up on the canister light switch turns on the pendant light (and not the canister lights, unless you want that, too).
I have similar stuff programmed with Home Assistant using Node-Red, but the normal automation stuff would work, too.
Home Assistant/Node-Red sees that Scene 2 (or whatever) has been called for, and then does whatever you want.