How to make transition effects cover only a small portion of the screen?

I've been experimenting with the various transitions in the program, but they seem to all assume that the transition covers the entire screen at once. If you use Dip to White or Dip to Black, the entire screen will dip to white or black, rather than specifically the clips you are transitioning between. If you use the Wipe effects, it will mostly work as intended for smaller clips, but it will assume the total wipe covers the entire project, so the actual time of the wipe will be much smaller than anticipated. If you use the Slide effects, the small clip will usually traverse the entire screen while it is sliding. Etc.

I understand the reason this is the way it is, but is there any way to localise the transitions? Make it so I can have a small clip in the corner of the project that has its own transitions completely separate from the rest of the project? It's just not worth it to complete every single mini-project seperately.