Set the cc field to be: Substitute ( List ( Contacts(StaffTO)::Email ); ¶; "; " ).
BTW, you may want to consider renaming your table occurence so that there are no paranthesis in them.
Of course, the List function. I know about it but often don't think to use it!
The brackets aren't in the TO name - I just put them there to identify that particular TO in my post. Probably quite unnecessary!