Multipoint Routing Algorithm

Question

Hi All,

I am working on a webbased routing solution which is basically for clubbing\creating the routes online using Google Maps for a transport\dispatch system.

I have to achieve below functionality but as of now i was never succeeded to do so,,please help

1. I have 300 customers information including Geocode\address. All are located with in 50 miles radius.

2. I have 30 Vans in my hand which need to deliver goods to the above 300 customers

3. Each van can take stuff for 30 customers.

4. Now i have to reduce this by optimizing the routes by shortest path\less time etc

5. I have used distance is parameter from the centralOffice and clubbed customers into diffrent groups but was never get good results.

is there any good algorithm for this or any suggessions

I want to develop something like http://www.xora.com/products_xroutes_overview.php

please help

Dheeraj