Get value of additional users from plan sharing options

If a member signs up and pays for X number of family members how can I get that number to use in another field displayed in the profile?

I'm using it as a limit for invites and for reference on the user profile.

Screenshot shows that the invites are limited by a field cb_additionalusers but I need this field updated by total number of additonal users purchased at registration.

Thanks
 

You can substitute in field values from CBSubs Options into CBSubs Integrations. So you can push their selection to a CB field using CBSubs Fields for example. For usage of these substitutions please see the bottom of the Integrations > Options > Display tab as it provides explanation and examples of how to use the CBSubs Options substitutions.