Output 1/3 or 1/4?

Is there a way to send to output 1 (xlr to board) and output 3 (to stage amp)?

The only way I can see to do this is by splitting on the grid. Often there are not enough grid lines available because I’m using one line for vocal.
Currently there are options to send to 1,2,3,4, all, 1/2, 3/4, but not 1/3, 1/4, 2/3 or 2/4.

If you send it to ”all” and pan left, it should only go to 1&3, leaving the other rows free for your vocal stuff.