@Override
    public boolean isSharingSupported()
    {
        return getGroupProviders().parallelStream()
            .anyMatch(GroupProvider::isSharingSupported);
    }
Returns true if at least one provider allows group sharing. Shared groups
enable roster sharing.

@return true if group sharing is supported.
xmppserver/src/main/java/org/jivesoftware/openfire/group/GroupMultiProvider.java