channel manager

I have a vacation rental management business. I have a channel manager called guesty managing it. I am looking to build a website through which new apartment owners can list their property and my channel manager will push it out to the booking sites like airbnb and [login to view URL] The guesty platform is robust and handles all the bookings and calendars I am happy the site uses this platform but i want the site to handle a few things 1 fees i wish to charge the guest a fee currently the money will go from airbnb and [login to view URL] to me then on to owner. Most managers charge the owner a fee i dont wish to do this i wish to charge the guest a service fee. this will be the money they pay say they pay 100 this is made up of cleaning and airbnb fee and accommodation fare. I wish to to deduct say 5% of that and pass on the balance to the owner via my site bank to bank transfer. 2 invoice a automatically generating invoice must be sent to guest to account or the fee 3 emails when a guest books a email is sent to the owner from airbnb to my channel manager then on to the owner, this has questions conversation and info on the price the guest is paying. I would like my fees accounted for here in these emails so the owner sees the amount of money they are getting with my fee already deducted as we have billed the guest they see the money they are getting not the money originally sent. So in the emails some of the info has to be changed while others parts of the email not changed So the finished product ie the website would have a section where people can list a property this is done via guesty it would have a path for people to book one o my places again done via guesty a way for a user to log on and see their bookings and calendar again all possible with guesty