How to view data in alphabetical order in a subfile

Folks,
 
In the below subfile, The records are displayed in the alphabetical order.
Now, what I want to know is how can I view records from a particular
customer name starting with alphabet say 'P' if when I enter P or PXXXXX in
the 'Position' to field?  
 
                                                   
                                                              Position to  .
. . . .              
 

 Type options, press Enter.

  2=Edit       3=Add     4=Delete                            
  
     Cust.Name     City                     A/c No

      A1                MUMBAI              10001

      A2                DELHI                  10002

      B1                HYDERABAD       20001

      B2                KOLKATA            20002

      C1                PUNE                  30001

      C2                CHENNAI             30002

      D1                BANGALORE       40001

      D2                NAGPUR              40002

      -                    -     
      -                    -    
 
Rgds
 
 
     
 
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