Allow downlink without wired downlink capable AP

It would be great if we could use AP's as wireless bridges, without the need for a wireless bridge capable device on both ends. For example, we have a site with multiple NWA210AX Access Points and want to extend coverage to an office using an NWA55AXE device. It seems like as long as the AP on the other end is smart-mesh capable, it should be able to create a downlink. I understand if it is a technical limitation, but if it is more of a licensing limitation, it seems excessive.