Investigate - Application Users via SystemUsers

[Splaxi]

/api/data/v9.0/systemusers

{"applicationid":"bb....38","isdisabled":false,"accessmode":"4","businessunitid@odata.bind":"/businessunits(1b.....48)"}

Need to work with /businessunits?$select=businessunitid,name,_parentbusinessunitid_value&$filter=isdisabled eq false and _parentbusinessunitid_value ne null