title: stripe API - possible to combine multiple invoices into one payment?
body: <p>i have a use case where its possible for a user to accumulate multiple unpaid invoices with a stripe subscription (which would be marked as overdue). The only way i see to pay the invoices via the API would be to pay each one as a separate manual invoice payment (thus producing X lines items on a users credit card). </p>
  
  <p>Is there any way to combine all unpaid invoices into one payment ?</p>