Newbie Template Issue

I plan to use a custom template. Most pages will be the same "look" with the exception of a vertical menu on the side which changes depending which section I am in. Is there any way to do this with a single template or do I need to create different templates for each of these situations (with a differnt snippet or chunk or whatever to use for the side menu)?

Any advice would be appreciated. Thanks

Make the container for your side menu a TV, with @INHERIT as its default content. Then, for each top-level parent folder/document, edit the TV to have the menu’s startID set appropriately, and all of that section will "inherit" the same menu.