If you create two different templates and then assign each one to two different menu items with category blogs on them, then the articles should use the template you use for each blog menu item. Saves you having to create two menu items for each article normally but you may still need to because of the custom fields unless there isarticles. You can use a conditional in theon each custom fields that will workfield based on the menu item for each blog then (use the also on child items option).