Most teachers in very large student body schools are willing to write generic recommendation letters for all schools that you are applying to. In this situation you could email the international admissions office of your potential college and ask them if its ok to receive recommendations by air mail from your recommender in a sealed and stamped envelope. Most teachers in Indian colleges are ok with this as they can make do with 1 recommendation letter and reproduce copies of it and sign and attest this.
Of course keep in mind that when you are requesting for someone to write your recommendation you have known them personally and you are in their good records. Sometimes few professors could make an exception and go that extra mile if they know and like you well enough.
Hope this helps.