So far I have not found a way to access the current datasource.page() from schema.parse() however, you can from datasource.change(). I ended up using the datasource.change() function to push the returned data row-by-row (including the page variable) into a second datasource object. So now every time the datasource fires, it automatically updates the second datasource with the data, including the page variable that I needed.
One thing to remember, the UIDs for the second datasource are different even though you are passing the UID from the first datasource. I set the schema.id in both datasources and utilize this when referencing a particular row of data.