The option "Inherit from refresh or replace to modify" is present in this Custom Contols just as in any element of design. Thus, you can use these controls in different databases.
I do not understand what this idea.

Vlad - I understand you can set up a template which the database with the Custom Control can inherit from. It is more that I would like to update code in one place and have multiple databases using that code. Instead you have to manage which design elements are getting updated in each database.

I would like the functionality to mimic subforms in this way. As a website Administrator it is so much nicer when someone asks for a change to the site to be able to make the change and see it reflected immediately across all the databases. Instead of telling someone they should wait until the design update propagates all the databases.