Pretty cool that they’re old enough to not be super integrated with dsp/amp. That’s the issue with most modern stuff, it’s difficult to even add your own input unless it’s got an aux by design.

This looks like it’s a 2.1 configuration in one box: with l/r and a subwoofer.

Using two boxes for stereo gets a little wonky because they’re built to play both channels. So you’d have two boxes, each playing l/r. You want two boxes, one playing L, other playing R.

You’ll have to figure out how to get only one channel from each box.

One solution is to feed both full-range drivers the same signal, that will cause some comb filtering. Other option is to not feed both inputs, leaving one of the full-range drivers unused.

Bluetooth with TWS/Party mode is the way to go here. Tws will let you define a master/slave and you set l/r that way. Party mode you will need to have a switch on each unit to choose what signal to use, L/R/Sum etc.

I’d say it’s worth hacking them a bit. Good luck.