In-wall line array wiring question

It sounds like you may be using professional line array components?  Otherwise I’d say switch speakers.  

However if you are, the professional solution to your problem is a professional amplifier.  Instead of going low impedance, you want to go high impedance, and high wattage.   Hook up your speakers in series for the full 24 Ohms and use something like the Crown XTi 1002 amplifier.  Bridged you will get about 1000 Watts / 8 Ohms.  The high wattage really translates into high voltage, which is what you need.  You’’ll get about 90 Vrms.  Assuming you wire them in series you’ll get about 30 V across each of the 3 components, which is about 110 watts / speaker.    You will need one XTi per line array. 

Note that due to the high impedance of 24 V the amplifier itself won't be current limited.  At full voltage (90V) swing it will only be able to produce about 330 Watts.  Point is, despite the 1000W/8 Ohm rating you won't be driving the amp anywhere near it's thermal limits.  Of course, avoid clipping, or reaching it's Voltage limts too, but this is kind of the ideal situation for using a bridged amp. 

I should have given you more broad advice. Any amplifier that is bridgeable at 8 Ohms will work with your 3 speakers in series.  The Parasound Halo A21 and A23 for instance will work  find.  I just recommended the Crown amps due to it sounding like you were making a pro like installation. 

I was actually looking at the XTI 1002 . I could run it normally, running two of the arrays @2ohms gives me 700 watts ch. That should be plenty per array. I’ll buy a second to run the center array. The only thing I lose is the musicality of an audiophile amp. My Coda will handle 2ohm loads but I don’t want to force it to stay there; wouldn’t be good long term.

If you run 2 in series and 1 in parallel with them you should be at about 5.6 ohms.