Dynamically filter a table to perform benchmarking

[Anonymous]

Hi all. I've been stewing on this all day and can't figure it out. I have two tables: 

1) A list of salesperson names and office locations:   

Salesperson in Table 1 has an established one:many relationship with Salesperson in Table 2, and Table 1 is set to filter Table 2

USERS TABLE

Salesperson	Office	Region
Jon Snow	Wall	North
Cersei Lannister	Westeros	Mid
Sansa Stark	Winterfell	North
Samwell Tarly	Wall	North

2) A list of salesperson names, customer names, offices, and sales amounts:

SALES TABLE

Salesperson	Customer	Sale	Office
Jon Snow	B	$4,500	Wall
Jon Snow	C	$5,000	Wall
Jon Snow	B	$650	Wall
Jon Snow	B	$500	Wall
Sansa Stark	D	$67,000	Winterfell
Sansa Stark	D	$1,200	Winterfell
Sansa Stark	D	$17,000	Winterfell
Sansa Stark	E	$12	Winterfell
Samwell Tarly	F	$100,000	Wall
Samwell Tarly	F	$99,000	Wall
Cersei Lannister	G	$17	Westeros

I have a report where the user selects a salesperson from the slicer, and we show the sales amount across customers for that salesperson. Pretty standard stuff. 

What I also want to do is to show the sales amount for other employees with the same office location or region, as a benchmark. So you'd see something like the table below, where you can see that Jon Snow has lower-than-average sales as compared to other salespeople at the Wall or in the North. 

Salesperson	Total Sales	Average Sales
Jon Snow	$10,650	$2,662
Wall salespeople	$209,650	$34,941
North salespeople	$294,862	$29,486

I'm pretty sure my answer lies in a Calculated table, but whenever I build one, I end up with all the expected columns, except they're empty. 

I've been using variations of the below measure to create the virtual table, but no matter what I try, I get sales = blank. Thank you in advance for any help you can provide!

DRAFT Table =

var _selectedvalue =CALCULATE( SELECTEDVALUE(Users[Office]),

         USERELATIONSHIP(Users[Salesperson],Sales[Salesperson]))

return        

 CALCULATETABLE(

    'Sales',

    'Sales'[Office] =_selectedvalue

     )

[amitchandak]

@Anonymous , try measure like

Measure =
var _office = Summarize(allselected(Table1), Table1[Office])
var _Region = Summarize(allselected(Table1), Table1[Region])
return
calculate(averageX(Values(Table1[Salesperson]), calculate(Sum(Table2[Sale]))), filter(all(Table1),Table1[Office] in _office && Table1[Region] in _Region))