Perl / Regex expert to create SpamAssassin rule to block messages containing specific string

Perl / Regex expert needed to create SpamAssassin rule to block messages containing specific string. I need a "body" checking rule which will pick up on messages which contain specific strings that always begin with two specific characters and end with numbers ranging from 6-9 which are preceded with a dash such as "-111222", "--111222333". I will provide exact examples of the specific string once the bid has been accepted. This should be relatively easy for any skilled Perl/Regex coder.