If the invisible signal idea does not work try the command 'couple to vehicle in front/behind signal'. You will have to name/number the signal, so you will have as commands, drive to t/mark/wait for 30 secs,uncouplez vehicle 1or2,drive to t/mark {this is to allow the engine to get to a set of points}, couple to vehicle front/behind signal.
I know it's long winded but if your at a station or use it a lot at the same place you can put the set of commands in a schedule library and give the copy commands from library {run round}. one command and all the ones you have saved under that name are followed.
__________________