When running multiple vuser groups with the same script i.e.

If that script references a data file (for parameters) then that data file is shared by *all* vuser groups.
e.g. my parameter called {values} has

When running, vuser group_b will error with these settings e.g.

i.e.

So 2 separate vuser groups still equals one shared parameter file (and settings).
Watch out [...]