Function Get-CommonPath( $Separator, $PathList ){
    $SplitPaths = $PathList | foreach { , $_.Split($Separator) }
    $MinDirectoryDepth = $SplitPaths | Measure-Object -Property Length -Minimum | Select -ExpandProperty Minimum
    $CommonPath = foreach ($Index in 0..($MinDirectoryDepth - 1)) {
        $UniquePath = @($SplitPaths | foreach { $_[$Index] } | Sort -Unique)
        if ($UniquePath.Length -gt 1) {
            break;
        }

        $UniquePath
    }

    [String]::Join($Separator, $CommonPath)
}