The Home/Categorize option in ribbon on Outlook 2010 toggles categories. If a group of mails is selected where some of the mails already have the selected category assigned then the action removes the category from those mails and assigns to the rest.

I view mails grouped by conversation and would like to repeatedly assign a category to all mails in the group.

I can clear all categories before assigning, but that would work only if the mails have only one category assigned.

Ideally, I would like to change the behavior of the existing button. If not, a different menu option or shortcut.

Is there a way to do either of this?