If you want to send a bulk email to a specific group of customers, first select the accounts.
Go to the Home tab in your function bar, then select Accounts and click on Search > Accounts.
Select your target group on the basis of categories, keywords, postcodes etc. and click on Search (Searching for accounts). Call up frequently used searches in the search dialogue by clicking on Recent searches and save them as Favourites so as to run the same search again at any time on the basis of current data.
A list of all accounts matching the search criteria will open.
Right-click to open the context menu for further editing or refine the list using filters if necessary (Show selected records, Show in new window or Remove)
Forward that list of accounts to another team member by clicking on Lists > Transfer in the toolbar.