How to add objects to NSMutableArray from another array

How to add objects to NSMutableArray from another array

I have an array "names" which contains names starting with letters a, b
and c.(like anju,chandu,basha,chitra,amith,baskar)
I have three NS mutable arrays as,bs and cs.
Now the question is how to get the names from "names" array assign the
names starting with letter 'a' to 'as' mutable array, names starting with
letter 'b' to 'bs' mutable array and names starting with letter 'c' to
'cs' mutable array?
Could anyone please help..
Thank you.