Create groups from custom platform

I’ve just created my first custom integration (see Dobiss NXT support), and one thing I’d like to add there, is to create groups (or at least some form of hierarchy) reflecting the groups created in the dobiss web interface.
I’ve already got this data of which entity belongs to which group available, but I haven’t found a way to set up these custom groups from my platform directly. Is that possible to do so?

Just checking - is this at all possible, or not?