GNDing HMC1118 RF1 or RF2 ports

Hi;

                We are using HMC1118 & ADRF5040 to build a 24x1 MUX and on the input and output of the MUX we are using HMC1118s for better isolation. Can we connect RF1 or RF2 of HMC1118 directly to GND or we need to put capacitor in between?

Regards;

Karo