Single Customer Portal, multiple Service Desk back ends

I would be great if Service Desk worked a little bit more like JIRA Agile Boards, allowing to mix-and-match multiple projects in the back end, but a single customer portal entry point.

We have a scenario where we want IT, Software, and other groups to have their own Service Desk back end, queues and projects, but would still like to offer a single customer portal front end to our users.

This would reduce the confusion on our users ( who can pick all their issue types from a single interface). As well as our agents, with each department working in their own backend with potentially separate SLA, queues, and other settings.