Automatic Email Integration in Google Docs App

I am a real estate broker and I have created my own real estate database/application for my team of agents using Google Docs spreadsheet application (I am very well versed in MS Excel, so I fairly easily was able to create this database). It's a collaborative system where my listings manager enters new apartments for rent (one listing per row) so my agents can see the listings and print out listing reports. There is a separate spreadsheet where agents enter their customer requirements (one customer per row) and the system matches listings for a specific customer when the agent inputs a "X" in the row for that customer. Agents must manually go down the list regularly to enter a "X" one at a time to find matching listings for their customers. I need the following: Instead of agents having to manually find the customer(s) they want to match listings for one at a time, I need the system to continuously and automatically match listings for all customers whenever a new listing is added or updated (ie. price change, availability date change.etc.) and automatically send an email report to the customers with their matching listings. I already have the matching system in place which works very well. I just need it to be automatic and evoke emailing.