Waiting for my league to fill up

I would love to start this season ASAP, but I have been placed in a 12 team league with only my team sitting in it. I notice there are other 1/12s in the same situation (with ATG-Post WW2, no DH teams...) Why can't these teams be combined in one league to speed up the process? How do I join one of these existing leagues?

Go to your team, click "leave this league" and join another one. Easy.

Yeah, I figured out that it was I had to change from ATG 7 to ATG 8 and now my league has 5/12 teams filled....There are about five other leagues with 1/12 each that could easily jump to our league, rather than wait for their personal random set league to fill.

Good chance if they are 1/12 they created the league with specific options which they want to use and changing leagues would require giving up those preferred options. The flip side of the desired coin of lots of options.