momwendy makes a really good point. Doubles teams that have time to practice together help a ton. We've dabbled with doubles teams that the only time they meet is during matches, and that doesn't work as well as people who play together a lot. So you may end up dividing the team by those that play socially weekday mornings during school, and those that play in the evening or on weekends to get around work, and have doubles partners be chosen from those they played with socially.
On the other hand, one year when my normal partner took the season off because she was pregnant I was paired with a lady who I never could practice with due to schedules. We went undefeated in league. We just meshed well. So it's not impossible to find good matches if there are some people that can't get into practice matches.