via hole grounding in layout

hi frnds iam designing a combline filter in the layout window of momentum(ADS) iam getting problem how to define a via hole grounding and how to place a via hole ground on to the resonators(since my resonators should be short circuited to ground) whether i have to modify the subrate layers and metallzation layers for creating a via hole ground.....? in the component pallete there is a component called via hole to ground is there whether we can place directly that component onto the resonators so that resonators will be shortcircuited to ground or not?
plzzzzzzzz help

Did you try the layer mapping in Momentum substrate?