I’d second @dave_dore 's approach - I regularly make copies of rack files (e.g. main reverb, solo reverb, guitar reverb are all the “same” rack, but copies). The disadvantage of this approach is that changes you make to one of them will not automatically be applied to the copies. Essentially, once you “clone” the rack, each copy will take on a life of its own and evolve separately.
For me, this is not a bad thing - over time, I created different “presets” in my guitar reverb rack that I don’t need in my main keyboards reverb, so I’m happy with my divergent copies, but if you want to make sure your copies stay in sync, you’ll need to use symbolic links - with the disadvantage that after any editing, you’ll have to completely re-load all instances (essentially re-start Cantabile) to make sure the change gets loaded into every instance.
Cheers,
Torsten