A Feature belongs to 1 Product only but Features can 'use' other Features across...

A Feature belongs to 1 Product only but Features can 'use' other Features across the tree, so you can track dependencies easily.

By the way, you can track dependencies at 2 levels: Features, like described above, and Tasks.

Then, your dependencies are display in both ways (uses, used by)

Was my answer clear ? Happy to help.