different character encoding systems

I am serving up an html page with characters encoded using two different encoding systems. These are directly encoded rather than using entity references and I am stuck with that for the time being. Can I mark up the different sections of the page so with a tag that tells the web browser which encoding system is being used, so that it can do the correct mapping for each section? I am only aware of the charset being defined in the metatag content attribute in the head section. Can it or another tag be used elsewhere on the page to switch character sets?
Is my only solution to convert the data so that it conforms to the same encoding system throughout the page?