There's no feature for this purpose in Publisher. The only suggestion I can
offer would be to put what you want "locked" on the Master Page & the rest
of the content as usual.
AFAIK, even professional PDF editors (Adobe Acrobat) don't provide the
capability either. If the nature of your flier can be handled by Word's more
restrictive layout capabilities you may be able to protect the document on a
section-by-section basis.
Regards |:>)
Bob Jones
[MVP] Office:Mac