Guestline is an award-winning Hotel Management Software (now part of Access Hospitality). Yes, it is possible to push booking information from BriteBiz to Guestline.
The BriteBiz - Guestline integration is made possible through an API connector like Zapier or Make.
Process as follows
Use a Zapier/Make account, and set up a Zap with a Webhook trigger that would catch the information triggers/Webhooks in BriteBiz.
Then set up an action on this Zap to send a Webhook (booking information) to GuestLine.
You would need to map the data fields BriteBiz sends to the data fields that GuestLine expects so that all information is correct.
Links below for further details.
BriteBiz Webhooks Here
Guestline API Here
BriteBiz does not provide direct support on setting up Zapier/API accounts; you would need to do this with your IT Manager.