Fixed components in a container?

Hi,

We would like pages created in experience manager to always have certain components: a title block and the seo component for example.

Is it possible for a prototype page to have 2 containers - the first repopulated with these mandatory components, and the second editable in the usual way. Ideally we would like this first container to be ‘locked’, in other words the content editor would be able to edit the properties of those preexisting components but not be able to remove them or add any other components to that container.

Is this possible? If not then is there an established approach to enforcing that certain editable components should be present?

Thanks for any advice on this,

David