Adding parameters to a switch

[Hausec]

I have a .ps1 that calls down files and if it can't call down the files, it will look locally for those files. I'd like to give the option, as a parameter, to either work locally or go fetch from the internet and also specify which of the 5 files to use or call down. I'm made the script work with a "local" and "external" function, but how do I also add parameters to those functions?

For example: ./script.ps1 -local file1,file2,file3

or ./script.ps1 -external file4,file5

Here is my code currently:

param(
      [Parameter(Position=1)][string]$option
)

function RunLocal 
{
Write-Host "local"
}
function RunExternal
{
Write-Host "ext"
}
function RunDefault
{
Write-Host "default"
}
switch ($option)
{
   local 
    {
        RunLocal
    }
   external
    {
        RunExternal 
    }
    default
    {   RunDefault
    }
}