Parameter set to limit the combination of parmeters

Function Do-Something
{
    Param
    (
        [Parameter(Mandatory=$true)]
        [String]$SomeThingToDo,
        [Parameter(ParameterSetName="Silently", mandatory=$false)]
        [Switch]$Silently,
        [Parameter(ParameterSetName="Loudly", mandatory=$false)]
        [Switch]$Loudly
    )

    #Do something
}

# This will not work because you can not use the combination Silently and Loudly
Do-Something -SomeThingToDo 'get-help about_Functions_Advanced' -Silently -Loudly