@AndrewMH 

Under the KASA app, you should be able to setup more than one property.  Each property will be accessible under its own tab and can be organized into rooms with its own set of devices. 

While I haven't made use of this feature to test it, the feature is clearly there in the app and so I assume the answer to your question is yes. It appears as though one login can access and control more than one property and naturally devices can be connected to different Wifi networks to do so.