Duplicating a Project from 16:9 to Square

I have just read "Duplicate projects and clips in Final Cut Pro for Mac" and tried it. However, my master 16:9 projects contain compound clips, including a master compound clip for treating the audio. Although the newly created Square clip is resized, the compound clips themselves are not, and appear to still be shared by the master. Breaking apart each compound clip, reapplying effects, etc, would be a big job.

Is there a procedure for creating a Square version copy of a Master 16:9 project that will contain new compound instances (that when edited won't affect the Master)?

thanks,

Geoff