Could probably be doable with database fuckery. Make a second community locally with an identical name, then in the backend swap some IDs around and make it think the posts were actually in the new one all along.

Granted, I haven't looked at the DB structure, so I don't know how plausible it is. If someone tries it, don't blame me if the instance breaks, do at your own risk.

But that creates a problem with potential duplicate name, but there is even bigger problem. By export I assume You mean taking ownership so adopting this community into the new server, who decides that? First come first served does not look good in my eyes as a good solution. Since that community is stored as a copy in other instances it should maybe just go into read only mode for eternity