ADG5412 unused switch termination

I am currently using the ADG5412, but only using 2/4 of the available switches.  The other 2 have their digital inputs tied to ground through a 1k resistor (switch is therefore open), with both the S and D on the respective inputs open.  Is there a better way to terminate this  switch?

I'm really wondering if the 1k is too big, if I should tie them such that they are closed, and if the source and drain should be tied to anything?

I am somewhat susceptible to noise with the 2 switches that I am using in my application, so the lowest noise termination for the extra 2 I am not using would be the most ideal solution.