Payment gateways

We are currently building a site and require assistance from someone with thorough understanding of US payment gateway options to help with its implementation. Our site will act as intermediary for bed and breakfast rentals and we want to facilitate the payment between the guests and the proprety owners. Ideally we would charge the guest directly our fee and have the host charge the guest directly for the stay. However we would like to provide a level of security and have the funds held, in some form of escrow or merely a hold etc. until the guest has arrived at the property, Likewise we need ways to hold security deposits on behalf of the hosts. We have a developer but looking for someone well versed in available gateways and knowledge of legalities involving holding credit card information, use of escrow [login to view URL] help with payment gateway choice and alocation. We are looking for a unique solution, not just charging the guest and then paying the host. Timing is 2 days from project start