Collaborator email in workflow

Hello Experts,

We are working with Workflows in CLM and when the workflow starts automatically two mails are send to the approval group:

1. One is the notification that you have been added as a collaborator

2. The other is the notification of an approval request

We dont want to send the collaborator mail, we just want to receive the approval request mail.

Is there a way to deactivate just one mail? Because we tried checking the "Do not send collaborator alerts or notices" in the approver role, but neither of both mail was sent.

Thanks in advance