How can you force a content area to be of a certain type (text, gallery, form)?

I want to be able to force a content area to be of a certain type. When I make a page on Edicy, it's typically been designed in a particular way that means certain areas are for photos, others for text, and others for forms. It's rarely jumbled up. I want, from code, to be able to make it so that an editor of my site doesn't even have the OPTION to mess the page up and put a photo-gallery in the title box!