In Motion, how can I set some layers to loop while others stretch with the generator on a FCP timeline?

I'm building a multi-layer Motion Generator project. I want to have some animated layers loop at a constant rate of speed with no end point while other layers stick to the beginning and end points on the Generator timeline. This way, when I lengthen the generator on the timeline in Final Cut Pro, some elements will continue to loop while other elements will stretch out and slow down to match the new Generator duration.

For example, I might have an animation of an oscillating/looping heart on the top layer in my Generator project. On another layer, I have a progress bar that progresses from the start to the end of the generator timeline.

In Final Cut Pro, I want the heart to continue to loop and oscillate at a constant speed while the progress bar progresses from the left-hand to the right-hand side. I have some Final Cut Pro clips that are longer or shorter. I want to overlay the clips with my generator from beginning to end. So, in other words, I want to stretch my generator to match the length of the clip on the project timeline.

Currently, when I stretch the generator from (for example) 5 seconds to 25 seconds, the looping heart animation will slow down to 1/5 speed to maintain the same number of loops in the clip over a longer time period while my progress bar does the same thing.

When I stretch my generator, I want the progress bar to slow down to match my clip length, but for the heart beat to remain the same rate and loop more times.