I am using 14 Platinum

I know I can adjust the playback of a video clip, but I am working on an animation and I want my multiple clips of varying lengths to all be the same time. Using playback speed adjustment isn't working for me because I don't know they rate it would need to be to be equal to the longest clip. Is there a step I am missing were I could enter something like "Track 11 playback speed equals 22 seconds"