FogBugz lets you do almost anything to a bunch of bugs that you can do to a single bug. Simply set up the filter that includes all the bugs you are interested in, go to the list page, check off the bugs you want to manipulate, and click on the appropriate action button.
To select any range of consecutive bugs, check the first box, then hold down the Shift key and check the last box.
Be patient; batch editing can take a while if you have selected a lot of bugs.
Tip: Clicking on the checkbox in the column header selects or unselects all the grouped bugs under that heading.
