There doesn’t appear to be a 6 cell version. There is a 4 cell version available in the Adafruit fritzing parts repository and a two cell version in core parts. If you only need breadboard and schematic (not pcb) you can use either 3 of the 2 cell versions in series or 1 of the adafruit 4 cell versions in series with a 2 cell version. If you want to make a pcb, then either you or more likely one of us will need to make a custom part. For a custom part we would need the data sheet with a mechanical drawing for the cell holder you want to use.
Peter