Thank you @hafniumzinc !
reading that helped… so it is possible to build the semantic model in textual files ![]()
This is part of an *.items file.
Group gErdgeschoss "Erdgeschoss" ["Location"]
Group gWohnzimmer (gErdgeschoss) ["Location"]`
Switch HM_Plug2 "Weihnachtsbeleuchtung" (gWohnzimmer) ["Light"] { channel="xx" }
It automatically translates to this in thesemantic model :

So the switch HM_Plug2 is now part of the Semantic Model. Important: it needs a “semantic class” the ["Light"] in my case in addition to the group, also the group needs a semantic class. in my case "Location"]
This might help you as well @Scuby
Thanks again!
This should be described in the “Semantic Model” part of the Documentation… as probably more people would like to do this in textual form.
Have a nice day