In my dial plan, extensions.conf, I have a the following variables:

SALES=Dahdi/9&Dahdi/10&Dahdi/11
CUSTSVC=Dahdi/12&Dahdi/13&Dahdi/14

I would like to get the value of the second variable from a file which contains only the Dahdi extensions string of people available. I have tried:

CUSTSVC=/home/richard/InTheOffice.txt
CUSTSVC=FILE(/home/richard/InTheOffice.txt)
CUSTSVC=ReadFile(/home/richard/InTheOffice.txt)

However none seem to assign the global variable with the value in the file. Anyone know how I can achieve this?