Hi Amol,
I understand your requirement is to have multiple languages with in single template.
It is very difficult to manage above mentioned way.
The easiest way would be to create the custom symbols, which can control the languages.
and maintain those symbols in the wwi header.
for ex., if you maintain the language symbols like ZLANG1, ZLANG2 & ZLANG3 in the template header, you can get the 3 open fields, when you access the transaction CBGL_MP01.
there you can enter the languages, what ever you want.
but in side the template, whole languages will be maintained. Languages will be filtered out, according to the entries you input in the transaction CBGL_MP01.
Let me know, still you have any questions on this.
Regards
kamal