The original is from gist/Jaykul
@(
[PSCustomObject]@{ Name = "A"; Value = 1 }
[PSCustomObject]@{ Name = "A"; Value = 2 }
[PSCustomObject]@{ Name = "A"; Value = 3 }
) | Group-Property Value
Name Value
---- -----
A {1, 2, 3}
@"
Name,MemberOf,Members
DevOps,Ops,Joe
DevOps,Ops,Phil
DevOps,Ops,Barb
DevOps,Dev,Joe
DevOps,Dev,Phil
DevOps,Dev,Barb
"@ | ConvertFrom-Csv | Group-Property Members | Group-Property MemberOf
Name MemberOf Members
---- -------- -------
DevOps {Ops, Dev} {Barb, Joe, Phil}