host and build website

Hi i am looking for a directory style website I am looking to list businesses and give each a page they are listed by area and business type with key words there are two types of user on the site casual business Each business has a pre made page and can log in to it. They can adjust their home page and use the site to search for suppliers that are listed on the site and can place ads on the site like job ads and items to sell. They can send queries to other businesses and can keep track of them and request quotes like casual users can. Each casual user by logging in creates a page that can be used to keep track of queries they have sent to businesses Each question a user askes (business or casual) can be sent to just that target of the question or it can be sent to many people each question is to treated like a string or freelance job with one question sent and user can look at question sent and a list of all the replies beneath from the user page. we also have a request a quote where people can explain what they are looking for and request a quote this is then put up as a job to bid for and invites to specific people can be sent (a bit like elance) I am looking for a reliable system that can very simply allow people to find what they want fast and send many people the same question fast. I am looking for the site to hold the queries and so a user does not get 20 emails of replies for fast looking through 20 replies or quotes i dont want a seperate pmb for each as they are annoying to open i want the pbm always open below the quote or first reply