Thinking a picture always helps ... in the image below there are 4 groups of effects. The bottom effect is my reference effect whose duration I want to match. The first 3 series of effects (3x9) need to be compressed, proportionally, down to the duration of my reference effect. When I attempt to perform a group alignment (selecting all effects within this image) only the first effect in each of the 3 series gets aligned to the reference effect; the remaining 3x8 effects are left where they are.
As an aside ...
Independent of the reference alignment feature, I can select the entire group of 3x9 and shift it left or right using the <Shift> key. All that's needed now is a way to grab the right edge of the group and shift it independently of the group's left alignment, contracting or expanding to the desired duration.
Perahps a candidate for future enhancement, but thought I would inquire just the same.