JSD features an Organization field that allows customers who are grouped into an organization to view support tickets raised by other users who are apart of the same organization (as long as the field has been set), more information on the field can be found here: https://confluence.atlassian.com/servicedeskcloud/blog/2016/09/group-customers-in-organizations.
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We currently have an Improvement ticket to better support the Organization field, the ticket can be found here: JEMH-4989 - Support for setting JSD Organizations field via Directive/Custom Field Default RESOLVED .
Issue notification subscription
In order for members of Organizations involved on the issue to be notified, they must have manually subscribed themselves to receive notifications for the issue in question. You can read how to do that here: https://confluence.atlassian.com/servicemanagementserver/managing-service-project-notifications-939926348.html#Managingserviceprojectnotifications-optinoptout
Below is a screenshot of how an issue will look after the current user has subscribed to receive notifications for it.
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One method that could be used to associate an email domain with a JSD Organization is to use a Project Mapping Domain Mapping Rule.
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