[Zope] dtml in structured text?

Dear list, I need to insert some more complex formating in structered text. Is there a solution to insert some dtml-call or python-script-call in structured text documents or does anybody know how to do it simply? An ideal solution would be: Some structured text .... ...<dtml-var 'formating-rule("some more structured text")'> ... again structured text. The whole text should be in **one file** that is rendered as structured text exept the formating-rule-block and possibly placed in the localFileSystem with localFSProduct sothat it can be dynamically updated. Thanks a lot for your replies, Elena