musiconhold_additional.conf
[acc_1]
mode=files
directory=/var/lib/asterisk/mohmp3/acc_1

musiconhold.conf
[moh_files]
default => /var/lib/asterisk/moh-native,r
#include musiconhold_additional.conf
; class definitions For A2Billing
acc_1 => mp3:/var/lib/asterisk/mohmp3/acc_1
acc_2 => mp3:/var/lib/asterisk/mohmp3/acc_2
acc_3 => mp3:/var/lib/asterisk/mohmp3/acc_3
acc_4 => mp3:/var/lib/asterisk/mohmp3/acc_4
acc_5 => mp3:/var/lib/asterisk/mohmp3/acc_5
acc_6 => mp3:/var/lib/asterisk/mohmp3/acc_6
acc_7 => mp3:/var/lib/asterisk/mohmp3/acc_7
acc_8 => mp3:/var/lib/asterisk/mohmp3/acc_8
acc_9 => mp3:/var/lib/asterisk/mohmp3/acc_9
acc_10 => mp3:/var/lib/asterisk/mohmp3/acc_10