It's been a while since I've used AE so I feel a bit rusty.

I'm trying to use markers to triggers a layer's opacity, which is quite easy, especially when using Dan Ebbert's solution. What I can't manage to do is to use the marker duration to say for how long I want this value to be triggered.

Here is one example :

A layer has a marker with "active" as a comment, and 10 frames in the duration field at frame 100, and another marker named "active" with 12 frames duration at frame 200.

I want to trigger the layers opacity to 100% from frames 100 to 109 and from frames 200 to 211, and have the layer's opacity set to 0% the rest of the time. 

Does any of you have a clever solution to do this ?

Thank you,

Salvador