Displaying MIN date based on criteria in calculated field of PowerPivot

Hello All

I have a database with a list of transactions with multiple fields, including:
Customer ID
Store ID
Item ID
Date
Price

I am wanting to add a calculated field that displays the first (or MIN) Date from the date column, looking at all of the orders where the customer ID, store ID, item ID and price are the same.

In the attached file I have shown what I currently have, as well as a solution using a helper column, and formulas I would use if I wasn't using powerpivot.

Any ideas would be much appreciated.

Thanks!

no idea how you use power pivot are you just looking for an all in one formula to use in it? this array
=MIN(IF(INDEX($B$4:$B$27&" - "&$C$4:$C$27&" - "&$D$4:$D$27&" - "&$F$4:$F$27,0)=B4&" - "&C4&" - "&D4&" - "&F4,$E$4:$E$27))

Powerpivot is a whole different scenario, where instead of using lookups, you create relationships, and pull related fields, etc....
I'm looking for some sort of a DAX measure, perhaps using the "calculate" function (a function exclusive to PowerPivot), but I can't wrap my head around it. Someone who has a more complete understanding of PowerPivot knows the answer, but I'm just not there yet.