Local Realty - Website Backend System

Hi, I own a small real estate company and am looking to built a nice backend website for my agents to use. The purpose of the website will start as a document storage site, with plans to add customer relationship management software, and marketing materials (Business Cards, Flyers, Etc). To start, this will be phase 1: 1. User Login and Password 2. Once Logged in, have the option to choose which part of the site they want to use (Document Storage, Marketing, CRM...in 3 large boxes that are clickable...Only 1st one will be available in this phase). 3. Once user has clicked on Document Storage and taken to the new page, there will be a dropdown box with 1. I am representing the Buyer. 2. I am representing the Seller. 3. I am representing Buyer and Seller. There should be an option on the Seller one, that they can add the buyer portion later if they end up representing the buyer as well. 4. A detailed information box will come in where the agent must put in various information (Client name, address, phone number, etc). 5. Based on the selection they made, a pre-selected list of documents they are required to have will populate. There should be a "Browse" button next to each document for them to upload the required document. 6. Once items are uploaded, a notification would be sent to the broker to review the documents. 7. Once items are approved by broker, agent is notified that the documents are approved. That is the main function of phase 1.