To assist with many different use cases, most noteably, allowing all users from a single customer to be able to easily sign up to JIRA and then see and comment on all the issues created by the colleagues we need: 'Dynamic Groups'.
The Dynamic Group will allow one or multiple domain names to be associated with it.
E.G. A JIRA Administrator wants to ensure that any users from their customer Domain that sign up to JIRA are automatically included in a group that has been setup for the company Domain which has permissions to view certain issues and projects. To do this:
1. A Dynamic Group called 'Domain' would be setup with two domains defined: domain.com, sub.domain.com.
2. Then when a user signs up to JIRA, if their email address features domain.com or sub.domain.com they will automatically be added to the 'Domain' group.
3. All Domain employees that sign up to JIRA will therefore automatically be allowed to see all Domain accessible JIRA content (dictated by Permissions and Issue Security Levels which refer to the group Domain).