The short answer is yes. But not the best solution. It would require a huge amount of set up especially for external customers. For Example, what are you supporting? how would you know which customers have which products and that might mean down to the program level if you are supporting software. You would also need to set all these up as parts and create the links to show what belongs to each customer. So yes you could do it but is it worth the effort as SSM would probably be an overkill. Obviously I do not know your business so I could be completely wrong. Have you considered using SSM as the engine and creating a new front end to simplify the creation of calls that would then feed the info into SSM?