$FormatEnumerationLimit=-1
$grouplist = get-localgroup
$array = @()
foreach ($G in $grouplist){ `
    $line = new-object psobject; `
    $line | add-member -membertype noteproperty -Name 'Group Name' -Value $G.Name; `
    $user = get-localgroupmember -name $G.Name | Select-Object -Property Name; `
    $line | add-member -membertype noteproperty -Name 'User' -Value $user.Name; `
    $array += $line`
}
$array | ft -wrap -autosize