This is basically what the Unsynced queue option is for.

You can't have low-level and unsynced people together in instance matching because it absolutely destroys the rotations and party structure you're supposed to be learning about at low levels. No synced tank, no matter how well geared, has a snowball's chance of dealing with an unsynced character's aggro. An unsynced healer won't be remotely as effective trying to heal someone with easily three to five times their own health. Any DPS coming from unsynced melee or magic roles is going to pale in comparison to the inevitable Holy/Gravity spam that would happen with unsynced healers, and DRKs and WARs are going to annihilate mobs before DPS classes can get off a single proper rotation.