Add Plugin to Global After Install

I have a WPMU network setup and in use with the Multi-DB plugin.

We have recently purchased and added a "CRM" plugin to work with Woocommerce on our network.

This CRM Plugin has it's own tables, and creates "customer" records from the existing "user" records. However, because the users table is global, the plugin is of course having trouble finding users to add to it's DB, rendering the plugin useless.

I know that there is configuration for global DB's for "supported" plugins, but if I know the name of the tables needed to be globalized, what is the best practice to do just that on a network that had already configured the Multi-DB plugin and installed it.

I need to retroactively add plugin tables to the global DB.