Apologies if this is a dupe, I had a look and couldn't find a similar request.
It would be great to add a new feature to "Edit and Share Dashboard", where you could select users or groups of users who can then edit the same dashboard.
We share dashboards across teams in our company. Most of our dashboards are public for anyone in the company to add.
Development Managers add dashboards that PMs create, and would often like to add gadgets, but cannot due to the current limitations.
Let me know if anything isn't clear.