Could you not create a module out of it so you can export that module and import it in the other projects? This way you only have to change one module and update that module in the other projects.
If you are using the Mendix Cloud, then you can just add constants to store your values. That way, when you deploy to an environment, you can set all the constants in one place and don’t have to work about maintaining things in the modeler.
MNow, what to do if you have a lot of different cloud environments? Then you are in luck. Mendix has an API that allows you to make settings for every environment:
You can maintain a file in whatever technology you choose that holds these settings. You can then build a mechanism that makes REST calls to set the settings for whatever environment you choose. You will need to find a technology to call REST, but you can set this up however you want and use whatever file you choose.