A special node type for Aliens 3x normal costs. The aliens commander would need to place an Entrance and an Exit cyst which can only be built around tunnel nodes acts as a TP for aliens, and gives Humans a target to destroy to shut down alien TP.
The alien commander must make a chain of these nodes like normal, they would cost 150 per node and must have a entrance cyst and the exit point is the exit cyst. The timer would be based on the amount of nodes between the Entrance cyst and Exit cyst maybe something like 2 seconds per node? If the exit node is destroyed while a player is "Teleporting" they are killed.
You could even limit the tunnel nodes to creatures that spawn from the lesser cyst so players can TP behemoths and such.
Just an idea. Im still new but it was my first rhought when I played Commander for them teh first time.