My first suggestion, do not use the tabs. You are essentially putting three directories on one page. It’s doable … but depending on what you do, you could make the page slow to load.
So… if I understand this right, you basically want to divide the categories between three pages so you do not have 300+ on one page to search thru, right?
Since you’re using cMap, you can choose to limit the category selection to specified root parent categories. See this FAQ. I think this will get you what you’re looking for.