You still should be grouped with friends, League usually is where you will see the most friends, that is still a priority, then after friends they do I think have a vague guide on how close in Q the teams are, but that will vary depending on how many are at that level on your server. If you want a weaker League make friends with weaker teams on your level.

For awhile, I had a 35T team in the same level as my main. When I failed to unfriend it before League draw, I would get a weak League, now it is no longer on my level, I have no friends my level so I face a League of closer Q to my team.