If you want to send an email to multiple mailing lists you can do this either by selecting the mailing lists in the mailing lists list box (ad hoc selection). Alternatively you can create a combined mailing list, which is useful if you want to send mail to a group of mailing lists on a regular basis.
Limitation: combining mailing lists is only possible for Built in mailing lists.
The mailing lists list box supports extended selection:
Note: When sending, dupplicates email addresses are ignored - the email will not be sent twice to the same email address.