For simplicity sake, why don't you just group them according to BJCP categories? We're all homebrewers and pretty familiar with the categories and sub-categories. For example, Milds, Southern English Brown and Northern Brown Ales would be under Category 11 - English Brown Ales. I suppose you can make it even more general and include American Brown ales too and just have the category labeled as "Brown Ales". Use your best judgment with stuff that doesn't necessarily fit style guidelines and group it with other beers its relatively close to.
I would not group German Hefeweizens with American Wheats or Belgian Wits but I would group Dry Stouts in "Stouts" along with Milk stouts, Oatmeal Stout, RIS, etc, etc.