Integrating Ticket Webhooks and Comment fetching

I am developing an aplication that helps me sort and classify tickets through webhooks. Whenever a ticket is created via a chat (WhatsApp or Internal Chat) conversation, ZenDesk triggers an webhook  that sends some of the ticket information. Then, I use the GET /api/v2/tickets/{ticket_id}/comments method for retrieving the comments in the chat. The problem is that this doesn't retrieve the comments that are in the transcript - this transcript only gets associated with the ticket once it's closed and it has the most vital comments for my aplication.  How can I acces this transcript while the ticket is still open?