Mono Switch on a line mixer

[BrianJ]

I have been working out a simple design for a little line mixer for my studio and I decided a mono switch would be a cool feature.  I am combining the left and right busses with a standard inverting op-amp "virtual ground" summing circuit (times 2).  My question is would I be making an effective mono switch if I just tied the op-amp's inverting inputs together?  The op-amp's outputs would remain separate as would the "+" inputs (though something tells me to combine those as well....).  Would a 3 stereo input mixer become a 6 mono input mixer or would I have problems with one op amp interfering with each other?

The concept is basically just to have a routing and summing box with some monitoring options.  No level controls, pans, inserts, or eq's and hopefully accomplished with only 2 good op-amps in the path.  I have a sketch that I can try to post, need to hook up my scanner.