With all probibility he can be. But there is no restirciton udner RTI that any other person cannot be appointed under RTI.
You can also apply to ACPIO who is a junior officer and equally responsible udner RTI.
Yes Aparna you are right.
Infact, we are working on making a searchable PIO database so that the effort by one person can be used by all.
I have prepared one draft Kushal is improving upon it.
Till the time it is ready i guess the alternative is to go through the post office route.