How do I automatically associate company to incoming reservation?

Hi there, 

We’re in the process of starting with a new OTA. 

How do I make an incoming reservation immediately do the following? 
1) create two bills: one for the guest (city tax + incidentals to be paid by guest); one for the OTA (prepays accommodation). How do I route specific items to specific bills?
2) to have the bill for the OTA automatically associate with the OTA 
(so guest remains owner; OTA is associated profile)

Thanks!