I've connected an iMac and a MacBook Air on my network. The MacBook Air is a login item on the iMac. I have to start the MacBook Air first before the iMac boots, or else the iMac doesn't see the MacBook Air. If I reboot the MacBook Air, or start it after I start the iMac, I have to reboot the iMac to make the connection again. Is there a way to reconnect the MacBook Air, or any other login item, without rebooting the iMac?