From 'Email members' in the administration menu it is possible to email all club members or members of club groups.
By default the email is sent to all club members. If you have set up some club groups you can select the group and press the button to only populate the list with members of that group. If you wish to remove members from the list select them (use Ctrl to select more than one) and then click 'Remove'.
Enter a subject and the message and then press send.