Hi kaandee,
I think, that a Via-GND-ing isnt the best solution at such frequencies...
Other problematics is the only 0.72mm material thickness.
In my opinion you have basically two possibilites:
1, you apply a small slot on the place of termination & do insert trough PCB manually i.e. 3 smaller smd resistors(minimum 0402, but their dissipation is limited to ca. 70mW per piece)_practically thickfilms, or special Rf types_and solder that both sides.
2, you calculate the longhole/slot at terminating point & do fill it with resistor paste...
Thes way has mor worse tolerances & expensiver...
If the dissipation is a limit_ it exists special termination resitors too; but their costs some more...
K.