I created a gallery and connected to a new (one page only) dataset.
Then I created another gallery on the same page and tried connecting to a different dataset.
This did not seem to work - my only choice was to connect to the first dataset.
I suppose I could create a new site-wide dataset on some other page so that I could reference it from my second gallery but that seems like a hack. Is it not possible to have two one-page datasets on the same page?