Variable intro/middle/end possible?

I'm looking to create a Motion Generator that I can use in FCPX to allow me to have variable length intro/middle/end independent of each other. I know I can use the "Build-in - mandatory" Marker type in order to force an intro length to be fixed and the middle part to be based on how much you stretch it in FCPX. What I'm looking for is the flexibility to use the same motion generator to allow me to have a short intro, long middle and short ending in one case, yet allow me to have a long intro, short middle and long closing in another case.

This is for our company logo branding and I want to be able to sometimes have a slower or faster intro to match the video it's being used with. For example, our aerial reel has nice smooth slow footage, so I want our branding animation to gently ease in, hold frame for six seconds and then slowly animate out. A different reel might be fast paced, so I may want to have the branding intro animate in quickly, hold for three seconds and then animate out quickly. All this should be fully adjustable depending on need.

Any way to build this in one Motion generator?

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