Hi,
since the idea of Rentalhive is to build alternatives to AirBnb and such, why not add the option to have co-hosts for properties, like AirBnb offers?
A co-host is someone who is not the owner of the property, but manages it for the owner (and usually gets paid a commission for it). And cohosts can manage multiple properties at the same time.
You can add all sorts of permissions to a cohost, like modifying the listing, blocking dates, etc, and it could get as complicated as you want. But at the very least, it would be a nice touch to initially give vendors/hosts a possibility to add cohosts with the ability to respond to messages from users. That would help owners to respond quickly to messages when they are themselves not available for whatever reason.
Hope this helps!