Hi @Alexander ,
maybe this is helpful to get started:
## AzureAD PowerShell module required
# Get AAD Groups and Group Memberships
$users1 = Get-AzureADgroup -Searchstring "Test1" | Get-AzureADGroupMember
$users2 = Get-AzureADgroup -Searchstring "Test2" | Get-AzureADGroupMember
$users3 = Get-AzureADgroup -Searchstring "Test3" | Get-AzureADGroupMember
# Compare Group1 and Group2
$compareObj1 = Compare-Object -ReferenceObject $users1 -DifferenceObject $users2 -ExcludeDifferent -IncludeEqual
$inGrp1andGrp2 = $compareObj1.InputObject.DisplayName
# Compare Group1 and Group3
$compareObj2 = Compare-Object -ReferenceObject $users1 -DifferenceObject $users3 -ExcludeDifferent -IncludeEqual
$inGrp1andGrp3 = $compareObj2.InputObject.DisplayName
# Compare Group2 and Group3
$compareObj3 = Compare-Object -ReferenceObject $users2 -DifferenceObject $users3 -ExcludeDifferent -IncludeEqual
$inGrp2andGrp3 = $compareObj3.InputObject.DisplayName
# Results
$inGrp1andGrp2
$inGrp1andGrp3
$inGrp2andGrp3
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(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)
Regards
Andreas Baumgarten