A similar option would be to rent Terran Union freighters by paying double supply.
Of course, any proposal involving letting foreign ships through Commonwealth warp points and later returning them would be a bit of a security issue.
A roleplaying reason for helping the Terran Union is that Athens will end up the closest habitable planet to Earth. So as a late minute site for evacuation in the face of Nemesis, the same number of colony ships could evacuate over twice the number of people, assuming that the colony ships were designed with enough tractors to rapidly load and unload.
The sooner Athens is terraformed, the better.
Athens could end up a multicultural, high population world with few transNewtonian resources of its own.
