Adding masks together while trimming them in the timeline

I am relatively new to Fusion and I really like it. I have read the manual and have gotten through most of the tools manual plus numerous video tutorials. However, I am finding that these manuals do not cover everything completely and I am learning new things by accident.
So here is my question. How do you add two polyline mask together and yet trim each mask to appear and disappear at different times? I plugged the first polyline tool into the second polyline tool with paint mode a default setting of merge. My second polyline tool plugs into a matte control foreground while my footage pipes into the matte control background. I want to cut a hole (alpha) in my footage. My footage range is 0 to 300. I trimmed my first polyline tool in the timeline in at 58 and out at 119. My second polyline tool is trimmed in at 119 and out at 200.
Now here is the problem, the matte control tool turns red anytime I scrub outside the in and out points of the polyline tools. Like for example with the first polyline tool, the in point is frame 58. Also the footage plugged in the matte control tool background doesn’t update until after the in point of the first polyline tool which is frame 58. The second polyline tool with input output of 119 to 200 doesn’t update at all. With other tools like blur, you can trim where you want the tool to effect the footage. Is this not the case with the polyline tool?
My goal is to merge two or more polyline tools together while controlling each polyline tools’ in point and out point independently.

Think about this: how can one mask influence the other (cut holes in it or merge or otherwise) if they're not both valid for the whole duration?

You can animate the level slider to control whether or not the mask influences the other practically, but they need to be active for the whole duration.

In Fusion trimming the tools is not the way to go most of the times. Animate the blend slider in the radioactive tab if you want to limit the use of a tool. It will have the same effect as trimming the actual tool, without running into red 'x'es.

Also just moving the polylines in and out of the frame with two adjacent keyframes is a perfectly fine way to control the amount of influence a polyline has.