I'm a bit confused...how do you use one transformer for two lights?
From what it seems based on what you said, the transformer (which has the male DC plug) is what is connecting to the timers...correct? If so, I would think that you could plug in the transformer to an extension cord to run that to the timer then...
But if it connects to the female DC plug on the fixture then that would be a bit of a struggle to reach the timer.
From how I understand it the timers go between the existing connection on your light's cable, so you would need a patch cable with the male and female ends of the same type if you wished to extend it to a second light that's farther away from the timer. It would be pretty simple to make if places like monoprice don't already have one.