I'm new to SharePoint and am building a collaborative internal website for issue tracking (one of the many SharePoint sites on this SBS machine). The site is already accessible from the outside of our network. We have a few customers who want to be able to login to our issue tracking system, post bug or change reports, and track the progress of their specific reports, as well as browse internal collaboration related to them. I'm sure SharePoint/SBS can do this, but I'm not sure how to set up the security.
I tried creating a new user in SBS for a customer, added a new role "Customer" with a default of only SharePoint Member privileges. From there, I know I can grant specific users access to certain SharePoint sites. But, from there, I don't know how to lock that user down to only be able to access parts related to them.
The site is still in the raw form, so I'm willing to make any large changes if necessary to the issue tracking system. I already have a field on the issue list for related customers, which is a domain user list. Using this, am I able to further lock down a single user to only see things related to them in the issue tracking?