How to modify montage blend in time dynamically?

I have a montage, its length is 1 sec, blend in and out time are 0.25 sec.
When I set the play rate is 1, it goes well.
But sometimes, I need set the play rate as 3. Then my montage basically not even playing.
How to modify montage blend in time dynamically?
Please help.

Is there anyone know about it?

You can try to use Play Slot Animtaion as Dynamic Montage