OP did so... /QUOTE]
Fine! Then the child has two "grandparents". NOT two sets of "grandparents" as you earlier expressed! If you wish to label step grandparents as grandparents or group apples with oranges, I suppose that is your prerogative.
Turning back to the core question . . .
Not only are you immune from being ordered to furnish support for your daughter's child in the sole capacity of grandfather - neither the child's grandmother nor her grandmother's husband (the other set, if you wish) would have legal standing to pursue such an action even if your capacity was that of a parent by adoption. Guardian ad litem proceedings would be required.
The other "set of grandparents" would be well advised to be made aware of 22NYCRR 130-1.1 (New York's Rule 11) in the matter of the assessment of costs and sanctions (including attorney fees) to be imposed in retribution for instituting frivolous and untenable litigation.