Hi,
I think the "problem" here is with SQL, once you group objects together SQL no longer knows who the objects are he combined. I don't think Lansweeper can do something about this.
I think you want to click on 23 and then get a list of the 23 items in stock in Göteborg, which is a list that does not exist, you will have to create it with a query.
I think the easiest way for you to solve it is without the "group" part in your function, and when you want only the results from, lets say Göteborg, you type Göteborg in the search field on top.
Hope this helps.