Hi modado,
I haven’t tried it, but after some search, this is all I found:
https://mikeudin.net/2020/11/11/cinema-4d-selection-to-object-split/
I have not used it in production, so test this carefully.
So far I can tell it works reliable. But please check the content carefully, the site seems to be hacked?!
IF you suggest this to Maxon. (see image), keep in mind:
https://www.maxon.net/en/support-center
The problem that I might see is that you can have overlapping selections. If you split an object based on that, at least two things might happen:
You get double polygons with different materials applied. This will cause trouble if things are left in the same position.
The code to split it will take only the remainder of the object, and if done in the correct order, it will look the same until you move things apart, and then perhaps something is missing.
Fingers crossed, the selections are made well, and the split is precisely based on that.
Enjoy