It appears grouping is not available in the deleted Items folder. You can however, create sub-folders to group specific email, but you will get an increase in performance issues.

To sort email by subject or from fields..

- Select the folder you wish to add this sorting view to. (deleted items / sent items)
- Within your ribbon, select the view tab then View settings.
- (option 1) Select "Sort" .. you can then choose how you wish to view your emails either by Subject, From, to, etc.
- (option 2) If you do not have the columns visible on the view bar within view Settings, Select Columns.
- In the drop down, select all mail fields. once selected choose the column you wish to add..

Hope this helps.