Email for several users harcoded en 'TO' field - Which is the correct delimiter?

In WebDesigner I need to send a confirmation email to several users (the users are harcoded in the TO field... they are not a in a SharePoint column).

I'm using the ";" as a separator.

Once it reaches that activity it throws an error about incorrect email recipient format.

What should be the correct delimiter to send emails to multiples email addresses?

Thanks!