First of all thanks for all the responses!! I tried the menugroupitem thingy, but I'm not sure this is the best way, so I'm going to try Brendens approach.
The only downside I see is that it's not that "visible" and "easy" for a customer with limited knowledge to change things. It's always some clicks before they can see to which menu a page belongs.
I'll keep you posted, and thanks again for all the replies.
Other ideas are welcome too, I'm just trying to figure out which is the easiest to maintain.
Also my apologies for the answer above, I noticed I was logged on with the wrong account :)