Aruba controller can create so called AirGroups to gather the Bonjour multicast traffic and reduce it to singlecast over multiple VLANs. You would need a controller and possibly Clearpass for that, which I guess is not realistic for you, no offense.
For more information see this:
https://community.arubanetworks.com/t5/Controller-Based-WLANs/What-is-the-concept-of-Airgroup-How-does-it-work-and-what-are/ta-p/185272
Another option, with which I have no experience, is: You could use multicast routing to achieve something similar, but I think the 1920 can not do that.