disabling prop spawn for users only

Ive been trying for a couple of days now but I really cant figure out how to stop users spawning props. The gamemode is DarkRP.

Thanks :3

[lua]function blockprops( ply, model )
if not ply:IsAdmin() then
return false

hook.Add( “PlayerSpawnProp”, “blockProps”, blockprops )[/lua]

in lua/autorun/server somename.lua, for ply:IsAdmin ( U can also add or ply:IsUserGroup(“vip”) )