Pre-filter the "Group-by" headings

[mlines]

I have created an online calender that creates a monthly activity programme for users to access.

I use the "Group by" facility to group the entries by the month so that monthly views (and printouts) can be taken. I pre-filter this in the list using the pre-filter capability in the data tab to only show the current date and forward, so that old programme entries disappear for the user.

However the "Group-by" headings at the top of the page still show the older entries and I would like to pre-filter the "Group by" facility to remove these, can anyone give me a pointer on how to do this?

 

[troester]

These are not "group by" but filter tabs.
As far as I can see they are buildt directly from the database (without prefilters).