An issue (or item) is a discrete single object which belongs to a single project. You can not have it in multiple projects. You can include it in many boards, and hence backlogs, if you want, but as it's a single issue, it won't be "independent" - any changes made by users on one board, or in the issue outside boards, will be reflected in other places, because there is only one item there.
If you need independence, create more issues (there's a clone option that might help)
Atlassian Summit is an excellent opportunity for in-person support, training, and networking.Learn more
Connect with like-minded Atlassian users at free events near you!Find a group
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no AUG chapters near you at the moment.Start an AUG