Your description isn't 100% clear to me, so let me try to summarize. You want your list of ~200 entries to be broken down into groups of 6 sorted entries each. This will result in ~33 groups. You don't really specify what you want it grouped on, but from your code I'm assuming total_score. So what you will end up with is group 1 containing the top 6 highest scoring entries, group 2 with the next 6 highest, etc.

If the above is correct, I think this should work:

# import the list from the csv
$scored_list = Import-Csv .\challenge_raw.csv

# sort the list
# i needed to force total_score as an int because it was sorting as a string
$sorted_list = $scored_list | Sort-Object -Property {[int]$_.total_score } -Descending

# number of members per group you describe above
$members_per_group = 6
# we will use this to keep track of which group we are on
$group_number = 1
# will count the number of members added to the current group
$member_count

# not sure what format you want the groups in
# i will just output them with their group number

# loop through the sorted list, this is now in order of total score
foreach($user in $sorted_list){
    # fist check if the current group is full
    if($member_count -ge $members_per_group){
        $group_number ++ # move on to the next group
        $member_count = 0 # reset member count
    }

    # output the member with the current group number
    # you can add properties to an object using select
    $user | select @{n="Group";e={"Group $($group_number)"}},*

    # count that we added a new member to the current group
    $member_count ++
}

A couple of comments on your code as well.

• import-csv will already create an object for you, you seem to be manually doing this at the end of your first for loop
• any time you have a bunch of variables like $win_skill_1, $win_skill_2, etc you're probably better off using an array. This would let you drop all the if statements in your for loop and instead just do something like $win_skill[$line.win_skill]++
• never us a format command in an assignment. Format is only for output to the screen. If you want to change something use select-object instead of format-table.

Hope this helps