How To Merge Distribution Groups

In order to merge distribution groups in Microsoft Exchange, you can use the Exchange Management Shell (EMS) to perform the merge. Here are the steps to do this:

1. Open the Exchange Management Shell on the Exchange server.
2. Use the following command to export the members of the source distribution group to a CSV file:

Copy code
Get-DistributionGroupMember -Identity "SourceGroup" | Export-CSV -Path "C:\Temp\SourceGroupMembers.csv"

1. Use the following command to import the members from the CSV file to the target distribution group:

Copy code
Import-CSV -Path "C:\Temp\SourceGroupMembers.csv" | ForEach-Object {Add-DistributionGroupMember -Identity "TargetGroup" -Member $_.PrimarySMTPAddress}

1. Once the members have been imported to the target group, you can use the following command to remove the members from the source group:

Copy code
Get-DistributionGroupMember -Identity "SourceGroup" | Remove-DistributionGroupMember -Confirm:$false

1. Finally, you can use the following command to remove the source group:

Copy code
Remove-DistributionGroup -Identity "SourceGroup" -Confirm:$false

Note that you should test the merge process on a test environment before applying it to production.

Also, you can use the same process to merge distribution groups in Office 365 with Exchange Online PowerShell.

Hi @Nina Brooks，

Supposing you are using Microsoft Exchange, you can create a mail flow rule to add the other distribution group as a BCC recipient in all mails sent to the first distribution group.

Let's say you would like all mails sent to DL1 to automatically go to DL2 as well, the mail flow rule can be created as follows:

Hope this can be helpful. Feel free to let me know if I have misunderstood anything.

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Connect to Exchange Online Powershell and try the following code. I recommend creating two groups to test with first and running this against those groups to validate it before you modify production groups.

Get-DistributionGroupMember -Identity "Source Group" | ForEach-Object {Add-DistributionGroupMember -Identity "Destination Group" -Member $_.PrimarySmtpAddress}