How to create different pieces sharing a common base ?

[hl037]

Hi,
I am designing guide rings for my router, and they all share the same base that fit my custom router base.

I designed the common part of the rings with the part design workbench, how could I fork it now ? (while still being able to change this common base once for all rings)

I also would prefer the common part to stay in the same file as the router base (by the way, they already shares a common sketch so that editing the base updates automatically the ring insert)

[Shalmeneser]

PartDesign_SubShapeBinder

[drmacro]

Based on the info given... I'd go with one or more Part Design Clones.

https://wiki.freecadweb.org/PartDesign_Clone