A few years ago I built a F1 style start lights system for a R/C Model Car track, if you are looking for one leg to go then the other etc, a modification of this timer circuit would work, but yes it should also be able to be done with a door sequencer.

I see the DX18 has this feature, each leg connected to individual channels through a electronic switch (same as you would normally use for lights etc), the radio then can be programmed for the delays.
As the DX18 is not available yet then the same thing should be able to be done with a door sequencer, just like it can control servos.