Real Estate and Rental Management

I am looking for someone to design and create a software package for a property portal. The portal will feature properties for sale by both agents and private sellers as well as people wanting to rent properties in various countries. I would like private clients properties to be uploaded automatically to the database but not live until confirmation of payment has been received. I want to be able to give agents abroad a login facility to enable them to add their own properties either individually or via an uploadable file format csv,excel etc. The software needs to be useable on domain names allowed via master control. Each agent profile must be able to be switched on or off any particular domain name. I would like an email system building in where clients can join for updates which will be automated on their specific choices. I would then like a specific rental website designed to cover rental properties worldwide - the rental side of the software above to be integrated into this site. The whole software package including icons, graphics etc must be owned by us. We may want you to do additional work on other projects if this proves successful. There will need to be a lot of communication between us to ensure that we both understand what is required and possibly further things added to the project - we will listen to your ideas.