Notify Pinned Members
Pinned members of a group are usually those with whom you regularly interact.
You can notify all your pinned members by using the Notify Pinned process.
First, select the files you wish to notify team members about.

Next, click on the Notify All Pinned Members button.

Enter the text of the message you want to be sent to the members of the group.

https://assets.suredrop.io/SureDrop-UserDocs-Images/SEN-SD-Group-Notify-NotifyPinnedMessage.png
When you have entered the required message text, click the Notify button.
See Notification Email for an example of the email a member will receive.