If you open your email box and click the actions box at the TOP then select all emails it's first on the list it will send all your emails green then click Delete button at the top. This sends all emails to the trash.

The other way to reduce your emails is to use your arrow keys to highlight the first email you don't want then click SPAM BUTTON at the Top if you do this each day you will not get any emails from that person again. This will help reduce your emails.
only problem as each group gets new memebers you have to spam them.

On the Left side is a Spam and trash button if you click on them it will delete the your spam and trash.