You can use CentralPlanner for more than one business at the same time. Accounts are separate, so the data is never mixed and the invoices are also issued separately. This also means that you must invite users for each account.
For users who work in several accounts, however, there is a convenient option for switching between accounts.
If you have users who should have access to several CentralPlanner accounts, then simply invite them to your second (or third ...) account with the same email address. The user will then always see a black bar at the top of their interface. This lists all the accounts to which they currently have access.
Users can now jump between accounts with one click and without having to log in again.
Users that you invite to only one of your several accounts will only have access to this one. And as soon as you deactivate a user in one (or all) of your accounts, they will of course no longer have access to the corresponding CentralPlanner accounts.