Here's my situation, followed by my question.
I have two areas of my home served with Outlaw equipment. In one area I have a 990 (still going strong) paired with the 7124 amp. For this system I currently run 5 channels of the 7125 for a 5.1 system. I use the 990 remote room outputs with the two remaining 7125 channels to run two outdoor speakers (no sub). Now my question.
I would like to add a remote outdoor location consisting of two speakers and a sub. I planned to use the second 990 sub out for a sub.
I thought I could use a speaker selection switch of some type to achieve this. I would like to be able to selectively run one out door location at a time AND when desired both outdoor locations simultaneously.
Many years ago when I was stupid (or stupid-er) I burned up an amp doing something similar - poor impedance matching I presume.

Any suggestions or opinions how to achieve this?
Thanks in advance.