I mean, you could theoretically use two usb midi converters, one for the norns, one for the aleph. This would work best if one of the usb midi devices is, like, a keyboard or something with female DIN connector, and one of the usb midi is, like, a regular usb midi with male DIN connector.
However aleph can only take one usb device at once so you wouldn’t be able to plug a grid simultaneously in this setup. Adding aleph support to norns is definitely the way forward!