Twisted Treeline Team Balance

Why is it possible that randoms can be matched against groups on this map? It makes no sense at all. You either have a group for this map or you get rolled, because chances are you'll always be against a premade or duo.

I've played 3 matches in a row on TT, every match I was against either 2 man duo or 3 man group, with all randoms on my team. How do I know? Because I asked the other team, and asked my own team.

I think for now I'm done with TT, because I'm sick of being against groups.