I am trying to make an interface where only the objects of a certain group are visible, when the corresponding folder tab in the interface is opened.

I'm using a multiparm tab group in order to allow for an unlimited amount of groups to be controlled. So if I have 5 groups, then only 5 tabs are needed, etc.

If I use a a series of radio-button folders I can read out the number of the currently selected folder tab with a ch(“”) expression.
But if I do this with a multiparm, it returns the total amount of tabs currently visible, not the number of the currently selected tab.

So my question is, is there a way to return the number of the currently selected tab in a multiparm tab group?