I have an issue with new ticket notifications which I could not solve using Google or the search function so I hope someone will be able to help me here

In my installation I have two agents: root@localhost and peter (my account which I am using). Now I flagged the root account as inactive and in the user profile set "New ticket notification:" to "No". My Account "peter" has been assigned to three groups: admin, stats and users.
Now for every new ticket, I receive three e-mails. One greeting me as "Hi Peter,.." and two greeting me as "Hi Admin,...".
In Admin => "Notification Management" I have the Notification Event "New Ticket Created" with the Recipient Group "Agent (all with right permissions)", Recipient Agents "Peter xy...") and the Recipient Groups "Users" highlighted - the two other groups are NOT marked.
Any ideas why I now receive new ticket notifications three times? One for the agent and two times for the admin?
Thanks,
Peter
PS: I use OTRS v3.0.5