Power Query -- Group-by-Result Expand

Question

Here's an example of my existing data set. I have unique parts (Part) grouped by what factory # (Factory) they're used in and when the parts started to be used in operation (Part Install Year).

Part	Factory	Part Install Year
1	100	2018
2	100	2018
3	100	2018
3	200	2019
3	300	2020
4	400	2019
5	400	2020
6	500	2018

Desired Output is below. I need to group all the related parts by the lowest numbered factory they are installed in (Part Grouping) and then calculate the earliest year any part was installed in that factory (Factory Install Year). I'm having trouble figuring out how to create the Factory Install Year. Thank you!

Part	Factory	Part Install Year	Part Grouping	Factory Install Year
1	100	2018	100	min of all Dates in Factory 100
2	100	2018	100	min of all Dates in Factory 100
3	100	2018	100	min of all Dates in Factory 100
3	200	2019	100	min of all Dates in Factory 100
3	300	2020	100	min of all Dates in Factory 100
4	400	2019	400	min of all Dates in Factory 400
5	400	2020	400	min of all Dates in Factory 400
6	500	2018	500	2018

Answer 1

Try

let  Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
#"Changed Type" = Table.TransformColumnTypes(Source,{{"Part Install Year", type number}, {"Factory", type number}}),
EarliestYear = Table.Group(#"Changed Type", {"Factory"}, {{"EarliestYear", each List.Min([Part Install Year]), type nullable number}}),
#"Grouped Rows" = Table.Group(  #"Changed Type", {"Part"}, {
    {"data", each _, type table },
    {"MinFactory", each List.Min([Factory])},
    {"EarliestYear", each try EarliestYear[EarliestYear]{List.PositionOf(EarliestYear[Factory],List.Min([Factory]))} otherwise null}
}),
#"Expanded data" = Table.ExpandTableColumn(#"Grouped Rows", "data", {"Factory", "Part Install Year"}, {"Factory", "Part Install Year"})
in #"Expanded data"