The alamo bowl gets to pick from the "remaining Big 12" from last year, and last years Pac 12, so Colorado could be selected against BYU as the "Pac 12" representative. I know they always make a big deal of conference records in bowl games, and here it would be guaranteeing a win and a loss.
From what I found, there has been 1 time in the last 45 years where two teams from the same conference played each other (non-championship)