Dear Richard and ALL
Thank you so much. It works fine. We need to incorporate U+200C (zero-width non-joiner) to our Unicode enabled Keyboard for handling such problem.
Regards,
Goutam
 
বাগ্‌দেবী
09AC:   ব  BENGALI LETTER BA
09BE:   া  BENGALI VOWEL SIGN AA
0997:   গ  BENGALI LETTER GA
09CD:   ্  BENGALI SIGN VIRAMA
200C:   ‌  ZERO WIDTH NON-JOINER
09A6:   দ  BENGALI LETTER DA
09C7:   ে  BENGALI VOWEL SIGN E
09AC:   ব  BENGALI LETTER BA
09C0:   ী  BENGALI VOWEL SIGN II