How to import polarion relations by ReqIF to RV&S

We got ReqIFs from Polarion with relations specified.
The only thing (e.g. compared to DOORS ReqIFs) which is missing in the ReqIF are "Relation-Groups".

WRC 4.2 seems to expect these Groups because there is no option to import the contained relations.
Is there a trick how to adjust WRC differently for Polarion ReqIFs, may be additional refactoring for the links/relations?