Hi Ferdinand!
Thanks for getting back in touch - yes I tried every possible export/import combination and read through header specs for alembic and found not much. In the end I tried blender and this specific Groom Exporter Plugin and even this route was rocky.
I made it work in the end tho - see video 
I try to see if I can access and read out the abc info now.
Maybe there is some way to port this to C4D...