Update groupheader after binding resources

[Santor]

In my schedulerview I like to add a count field in my group header.
This count field must show the total appointments there are in the schedulerview for this group. (so I want to update the group header after insert/delete/change a appointment by the user)

Does anyone know how to do this, is it even possible?

[Santor]

I found the solution for my question.

I use the iNotifyPropertyChanged interface to update the count field.