If you want to have Powershell automatically manage lists of mailboxes these scripts can help with that process. You'll still need to tweak them a bit to get them right.
Office 365 - Add to Distribution Group
Create a text file with one email address per line. Then run this. Modify the file path and the group name
#Need to use module ExchangePowerShell
Install-Module -Name ExchangePowerShell -Scope CurrentUser -Repository PSGallery -Force
Write-Host "Login to the Exchange account where your Groups are set. We'll use this to add groups."
Connect-ExchangeOnline
# You'll need to change the filename
# The file should have one email address per line
foreach($line in Get-Content C:\Users\pmend\Desktop\users.txt) {
# https://docs.microsoft.com/en-us/powershell/module/exchange/add-distributiongroupmember?view=exchange-ps
# -Identidy = Group we want to add the user to. Can be Name, Alias, Distinguished Name, Canonical DN, Email address or GUID
Add-DistributionGroupMember -Identity "My Group" -Member $line
Write-Output -InputObject $line
}
Exchange - Find contacts in Distirbution Group and add to mailboxes.txt file
For Exchange this will loop thru the members of a distribution group and add them to the mailboxes.txt file.
#Need to use module ExchangePowerShell
Install-Module -Name ExchangePowerShell -Scope CurrentUser -Repository PSGallery -Force
Write-Host "Login to the Exchange account where your Groups are set. We'll use this to add groups."
Connect-ExchangeOnline
#remove the mailboxes.txt file
Remove-Item -Path C:\sigparser\mailboxes.txt
foreach($member in Get-DistributionGroupMember -Identity "SigParser Mailboxes") {
Write-Output -InputObject $member
$name = $member.Name
Add-Content C:\sigparser\mailboxes.txt "$name"
#TODO: Grant delegated read access to mailbox.
}