Either the solution to this could be very simple as I am about to suggest or I may have mis-understood the question.

If you wish to group your links  into several categories so that you have the expand  collapse capability, you can simply add columns based on those categories in the link  web part.
Now create a grouped view based on the category and where ever you wish to display the grouped listing, modify the web  part to use that particular view.

It should do the trick.