Put referenced node into a group in .ma file code

How can v put a referenced node into a new group in a .ma file?
For e.g; see my .ma file:

//Maya ASCII 2009 scene
file -r -ns "sfr" -dr 1 -rfn "sfrRN" "\\ibm-118/Work Area/char/sfr.ma";
requires maya "2009";
select -ado;
group -n "CHARACTERS"; xform -os -piv 0 0 0;

sfr.ma contains just a sphere, say sfr1.
I need to put it inside a group named "CHARACTERS".
I am not running this by opening the scene in Maya - I need to write it in that .ma file itself.
But the above code wont work.
Any way to do this..? Plz help.

maya ascii files are NOT MEL theres no such thing as group and xform in a maya ascii file. You must contend yourself with using following subset of commands:

file
requires
currentUnit
fileInfo
createNode
setAttr
select
connectAttr
lockNode

which is basically all you will ever need. Since a group is just basically the same thing as:

createNode transform -n "CHARACTERS";

you should use that. But your file is actually far more complicated than that. your file would look something like (didnt test very thoroughly):

//Maya ASCII 2009 scene
//Codeset: 1252
file -rdi 1 -ns "sfr" -rfn "sfrRN" "//ibm-118/Work Area/char/sfr.ma";
file -r -ns "sfr" -dr 1 -rfn "sfrRN" "//ibm-118/Work Area/char/sfr.ma";
requires maya "2009";
currentUnit -l centimeter -a degree -t pal;
fileInfo "application" "maya";
 
createNode transform -n "CHARACTERS" ;
createNode reference -n "sfrRN";
  lockNode -l 1 ;
connectAttr "sfrRN.msg" "CHARACTERS.ihi";

Tough you may want to actiually ad the default cameras or your order will be wonky So your scene should look like:

//Maya ASCII 2009 scene
//Codeset: 1252
file -rdi 1 -ns "sfr" -rfn "sfrRN" "//ibm-118/Work Area/char/sfr.ma";
file -r -ns "sfr" -dr 1 -rfn "sfrRN" "//ibm-118/Work Area/char/sfr.ma";
requires maya "2009";
currentUnit -l centimeter -a degree -t pal;
fileInfo "application" "maya";
createNode transform -s -n "persp";
	setAttr ".v" no;
	setAttr ".t" -type "double3" 28 21 28 ;
	setAttr ".r" -type "double3" -27.938352729602379 44.999999999999972 -5.172681101354183e-014 ;
createNode camera -s -n "perspShape" -p "persp";
	setAttr -k off ".v" no;
	setAttr ".fl" 34.999999999999993;
	setAttr ".coi" 44.82186966202994;
	setAttr ".imn" -type "string" "persp";
	setAttr ".den" -type "string" "persp_depth";
	setAttr ".man" -type "string" "persp_mask";
	setAttr ".hc" -type "string" "viewSet -p %camera";
createNode transform -s -n "top";
	setAttr ".v" no;
	setAttr ".t" -type "double3" 0 100.1 0 ;
	setAttr ".r" -type "double3" -89.999999999999986 0 0 ;
createNode camera -s -n "topShape" -p "top";
	setAttr -k off ".v" no;
	setAttr ".rnd" no;
	setAttr ".coi" 100.1;
	setAttr ".ow" 30;
	setAttr ".imn" -type "string" "top";
	setAttr ".den" -type "string" "top_depth";
	setAttr ".man" -type "string" "top_mask";
	setAttr ".hc" -type "string" "viewSet -t %camera";
	setAttr ".o" yes;
createNode transform -s -n "front";
	setAttr ".v" no;
	setAttr ".t" -type "double3" 0 0 100.1 ;
createNode camera -s -n "frontShape" -p "front";
	setAttr -k off ".v" no;
	setAttr ".rnd" no;
	setAttr ".coi" 100.1;
	setAttr ".ow" 30;
	setAttr ".imn" -type "string" "front";
	setAttr ".den" -type "string" "front_depth";
	setAttr ".man" -type "string" "front_mask";
	setAttr ".hc" -type "string" "viewSet -f %camera";
	setAttr ".o" yes;
createNode transform -s -n "side";
	setAttr ".v" no;
	setAttr ".t" -type "double3" 100.1 0 0 ;
	setAttr ".r" -type "double3" 0 89.999999999999986 0 ;
createNode camera -s -n "sideShape" -p "side";
	setAttr -k off ".v" no;
	setAttr ".rnd" no;
	setAttr ".coi" 100.1;
	setAttr ".ow" 30;
	setAttr ".imn" -type "string" "side";
	setAttr ".den" -type "string" "side_depth";
	setAttr ".man" -type "string" "side_mask";
	setAttr ".hc" -type "string" "viewSet -s %camera";
	setAttr ".o" yes;
createNode transform -n "CHARACTERS" ;
createNode reference -n "sfrRN";
  lockNode -l 1 ;
connectAttr "sfrRN.msg" "CHARACTERS.ihi";

PS: make sure your application actually writes foles in windows-1252 format

Thanks Jooja. But one pbm now: What if there are multiple references needs to be grouped under one? For e.g;

//Maya ASCII 2009 scene
file -r -ns "sfr" -dr 1 -rfn "sfrRN" "//ibm-118/Work Area/char/sfr.ma";
file -r -ns "box" -dr 1 -rfn "boxRN" "//ibm-118/Work Area/char/box.ma";
requires maya "2009";

createNode transform -n "CHARACTERS" ;
createNode reference -n "sfrRN";
lockNode -l 1 ;
connectAttr "sfrRN.msg" "CHARACTERS.ihi";
createNode reference -n "boxRN";
lockNode -l 1 ;
connectAttr "boxRN.msg" "CHARACTERS.ihi";

.... This is not a valid .ma file.
The error shown while open in Maya is:
'CHARACTERS.isHistoricallyInteresting' already has an incoming connection from 'sfrRN.message'

... ihi attribute is already connected.
Is there any way to group multiple references under one group?

Thanks.