How do you give a modifier to everyone at the start of the game ?

[TheWaWPro]

I made mountains passable so I could make them workable but I don't want units to be able to actually pass through mountains. Right now I have it set up so after you settle your capital and get the palace building how do I give it to everyone including city states so they get it straightaway.

    <Modifiers>
        <Row>
            <ModifierId>PALACE_DENY_GRASS_MOUNTAIN</ModifierId>
            <ModifierType>MODIFIER_PLAYER_UNITS_ADJUST_VALID_TERRAIN</ModifierType>
        </Row>
    </Modifiers>
    <ModifierArguments>
        <Row>
            <ModifierId>PALACE_DENY_GRASS_MOUNTAIN</ModifierId>
            <Name>TerrainType</Name>
            <Value>TERRAIN_GRASS_MOUNTAIN</Value>
        </Row>
        <Row>
            <ModifierId>PALACE_DENY_GRASS_MOUNTAIN</ModifierId>
            <Name>Valid</Name>
            <Value>false</Value>
        </Row>
    </ModifierArguments>
    <BuildingModifiers>
        <Row>
            <BuildingType>BUILDING_PALACE</BuildingType>
            <ModifierId>PALACE_DENY_GRASS_MOUNTAIN</ModifierId>
        </Row>
    </BuildingModifiers>