QuickBooks Online supports, what they call, child accounts.  These accounts can be linked to the parent customer record.  So these child accounts can use the same parent email address.

However, when you try to sync these child accounts to Rerun, a sync error occurs since the email address already exists for the parent in Rerun.

What you can try is to use a “+1” before the @ symbol in the parent email address that is on the child record. Some email servers (i.e. Gmail) allow this as an alias.  Any emails sent to this “+1” address will go to the main email (without the +1) and this will avoid the sync error for an existing email address in Rerun.

Example: parentaccount@mycompany.com as the parent email and parentaccount+1@mycompany.com as the child email. If needed,  +2, +3, etc can be used.

Please Note: This may also be a potential solution in other situations where there are duplicate email addresses that can all be pointed back to the main, or parent, email address.