This can be accomplished again with a calculated expression doing a sub-query on Active Directory. Depending on how many records you are pulling, try not to do too many as it can impact performance since you are doing individual queries for a single property:
$adGroupList = 'BI_FINANCE_FULL','BI_FIN_EXP_FACILITIES_FULL_R1'
$results = foreach ($group in $adGroupList) {
Get-ADGroupMember -identity $group -Recursive |
Get-ADUser -Properties * |
Select-Object @{Name='Group';Expression={$group}},
displayname,
name,
employeeID,
Department,
title,
physicalDeliveryOfficeName,
Manager,
@{Name='ManagerName';Expression={Get-ADUser -Identity $_.Manager | Select-Object -ExpandProperty DisplayName}},
sAMAccountName,
givenName,
surname,
UserPrincipalName
}
$results | Export-Csv -Append “C:\temp\GetADGroupMember4.csv” -NoTypeInformation -Encoding UTF8