How to loop an imported GIF in After Effects and be able to replace it with another Gif

Hey, I managed to loop my 90 Frames (3 seconds) Gif in After effects so that it does not stop after 3 seconds and keeps playing.
1. Add timeremap. 2. extend the layer. 3. add
loopOut()
or 
loopOutDuration(type = "cycle", duration = 0).

The problem with this is that I cannot simply replace the gif with another gif later on, I have a after effects script which loops through my 100 Compositions and replaces the gif layer with another gif from a folder.
Those gifs have different lengths.
When the initial gif was 3 seconds long and I replace it with a 6 second gif it keeps looping at 3 seconds and doesnt play the full 6 seconds.
Any solutions to that?