It is possible to group unsent invoices for an account into one invoice by enabling 'Invoice Grouping by Account'. This option can be enabled under:
Company > [Company/billing account name] > Company details
When Invoice Grouping by Account is is enabled, each new invoice you try to generate for that account, will be wrapped up into the last unsent invoice for a specific patient.
In this example, you can see that invoice #26 was raised on the 06/03/2019 for a Consultation, because the invoice was never sent, all subsequent appointments for the same patient have been wrapped up into the same invoice #26.
It is important to note that any unsent payments generated before Invoice Grouping by Account has been enabled, will not be grouped.
Note: If invoice grouping is required not specific to each patient account then the 'Invoice grouping by account' setting should not be ticked. The system will then group invoices by company and not be specific to each patient.