Bulk Upload and Data Feed Transfer and Upload

I need a software editor and data feed which I can provide real estate portals and websites for bulk upload of properties with individual details and several offices dealing with each sale. This should do the following: 1. Provide a data feed that websites and property portals can insert in their website/server to take a feed from us if requires by their account users. 2. A piece of software to copy (without deleting information of properties on their own desktop software) properties and property details (description, prices, information on rooms and measurements etc), photos into our software editor matching closing our codes and category for listings, namely, flats, apartments, houses etc as seen in our search page. 3. Allow companies to bulk upload properties for all its branches, up to 50- 100 branches with contact details and set properties to upload into the specific branches selling individual properties. 4. Allow users to enter their username, password and select the type of Listing package (which would be what already purchase in the control panel) to upload their listings. This is to ensure that upload is being done by registered users who already paid for their listings. 5. A system setup on our site which allow us to accept data feed from other websites and portals which enable properties from other portals and sites to feed and upload properties into specific categories on our site for individual account setup where subscription is already paid. Another version of this software for free subscription trial would be needed as well. 6. Job will include a small customisation of the script to allow subscribers to sellect at sign-up and on the control panel where they are Private or Company subscribers and if company, an automatic homepage added where they can have a shop front photo in the centre, contact details and a link to see properties they are selling. A link of their home page will be automatically created and email to them with this stored with their account details seen when they and the administrator login. 7. Ajust the inventory system to accept unlimited listing at set price in addition to listing for a minimum amount. 8. Data feed should enable transfer between websites and portals 9. I am not technical so do not fully understand how data feeds work but would like to have a datafeed in addition to the software for bulk upload mentioned, which can be ajusted easily with no technical knowledge - such as changing url, user, password etc that I can give website owners to insert on their server to feed their properties into our portal on the same principles discussed in paragragh 4 above. You must be a PHP expert comfortable with working with third party script and a minimum of 2 yrs experience. Experience in real estate web development or work of this kind is welcome.