You can view just one category, but you can’t select multiple and omit one.
Directly under “bbs” in the menu at the top of the page is “all categories”, which is the standard preset for viewing. Click it to open a pull-down and then you can select any one category to view. Since they don’t currently have radio buttons on the pull down - which would allow multiple selections - right now it’s an “all or one” choice.
