How can I add a group to a category/contacts from a list of recipients from a previously sent email?

Is that the only chance I have or is there another way to do it after-the-fact?
How can I add a group to a category/contacts from a list of recipients from a previously sent email?
First you must have all contacts in your address book.


1. From your Yahoo Mail page, click the Contacts tab.


2. Check the boxes next to the names you want in this group (category).


3. Click the "Add To Category" tab above the address book.


3. In the new drop down menu, click on "New Category." 4. Type the title of the category in the box that opens in the upper left. Click OK.


4. When you wish to send an email to the group, click on "TO" to open the address book.


5. Click on "Categories" at the top right corner of your mailing list, for mailing.


6. When your list of categories opens, check the box next to the "title" of your group, go to the top and click on "Insert Checked Contacts."