This should be easy

hey guys please let me take a couple of minutes of your time…

i have a BIG XML file with lots of info on it (Postcodes) so everything works BUT it seems to crash out everytime you type in a postcode, because its all in one file, i now want to create seperate XML files with each set of postcodes for example, A.XML will have all the postcodes beginning with A, and B.XML will have all with B in it, so now i need to know how to do this, i have a search box and when a user types, OL10 i want it to goto the “O.xml” file and check through it, and so on, please can anyone help, cheers!