forgot to meantion that this is a CI db rule which does not have the option [assignment to person; email]. the assignment to workgroup won't work about the CI is assigned to groupA but the email needs to go to groupB which has 3 people. If I remove the brackets, the email only goes to the first email address. I also tried a semicoln between email address but that doesn't work either. Any other ideals?
If you hard code the email address, it must be without brackets. Example: firstname.lastname@example.org
If you use the email address of a person playing a role for the CI, then it must be in brackets. Example: [Owner;E-mail] In this case, the field you use must be of Person type (and the Person needs to have an email address).
A final possibility is to have a field that contains the email address you wish to use. Example: [FieldWithEmailAddress]