I would use a pivot table to summarize data by Store #.

For more info on pivot tables, see here:
http://www.cpearson.com/excel/pivots.htm

Dave

Treat your data as a database, then on the sheet where you want the filtered
data to appear, go to Data->Import External Data->New Database Query

If you walk through the steps there, you'll see how you can identify the
Excel file as the database, and the range of data as a table.  Use the help
file in Query to learn how to create a parameter query linked to a cell, and
plan for that cell to hold a store number.  Once you've created your query
and identified the cell, you can change the cell value and run the query.  
It'll bring in all the pertinent data

I understand the limitations of Xcelsius and am new to Office Online.
The idea here is to create a serial number by store that a vlookup formula
can find.
Column A concatenates C&B
Columna B use an If formula that re-sets the serialization to 1 as the store
number changes B3=IF(D3=D2,1+C2,1)

1    A    B    C    D
2    Concatenate.Serial    Store #     Employee name
3    101    1    10    Bob
4    102    2    10    Jane
5    103    3    10    Kelly
6    121    1    12    Ted
7    122    2    12    David
8    123    3    12    James
9    124    4    12    Carrie
10    161    1    16    Joe
11    162    2    16    Kristin
12    163    3    16    Al
13    164    4    16    Nick
14    165    5    16    John
15               
16    Input Store number        12   
17    Concatenate.Serial        Employee name
18    121    1        Ted
19    122    2        David
20    123    3        James
21    124    4        Carrie
22    125    5       
23    126    6       
24    127    7       
A18=$D$16&A18 and copied down           
           
    Formula
D17=IF(B17>COUNTIF(C2:$C$13,$C$15),"",VLOOKUP(A17,$A$2:$D$13,4,FALSE))   
The countif determines how many employee's per store.
I hope this helps.
Charlie_Brown