Animator: Transition from any state in a Sub-State Machine to another state.

Is there any way to easily transition from any of the states in a Sub-State Machine(SSM) to another state? I have two SSMs in my base layer: Ground and Air. Inside Ground I have two other SSMs, Idle and Moving, each with several states and blendtrees. Air also has a few states and blendtrees. I would like to transition from SSM to SSM regardless of what state I'm currently in inside a state machine. For example transition from any of the states inside Idle to the Air SSM when my character is no longer grounded. Right now I have connected each of my Idle states to the exit node if my character is no longer grounded or idle, which is severely repetitive. So, is there any way to do this with just one transition per condition, or is there a better way to accomplish this?

(Forum post: http://forum.unity3d.com/threads/animator-transition-from-any-state-in-a-sub-state-machine-to-another-state.321897/)