For each sheet, use the "Make reference card" command, then rename the sheet from "Reference Card" to something else, then repeat. The command will overwrite any existing sheet named "Reference Card" sheet but will leave it alone if the name is changed. You'll end up with four sheets with one card each.
Once you have the reference card sheets, you can copy and past the cells from one into another, appending the cells below the previous one using the general editing features of Google Sheets.
Cell A1 of each sheet determines how the QMP treats the sheet. Make sure it still has "Sip Puff Reference Card" and the sheet will be skipped during the download of the CSV to the Quadstick.