I highly doubt this will accomplish your goals and will likely create more problems than it solves. It would help greatly if you would share what equipment you’re currently using along with a bit about your room and speaker positioning.
Shortcut or badcut?
Is there some point to try to add a bit more air to my speakers, using the 'second set of speakers' switch on my receiver? If I punch on speakers 'A' AND 'B', with a set of same-impedance, higher-reaching speakers (maybe just some smaller units) on the second button, would that possibly attain my result, or is this just a bad idea?