[Serusers] LCR module

Hi All, Sorry about this post but i just can't figure out the logic: i'm using lcr to send calls to pstn, when my user dials a number that begins with 00 i re-route it to my termination providers. e.g.: if ((uri=~"^(sip:)?00[0-9]*@([a-z]+\.)?mydomain.com") || (uri=~"^(sip:)?00[0-9]*@22\.22\.22\.22")) { strip(2); prefix("1234"); if(!load_gws()){ sl_send_reply("500", "Internal server error, unable to load gateways"); break; } } fortunately i have the same prefix on my termination providers. so on my lcr table i have defined all country codes to have the 1234 prefix, e.g 12341 for US , 123465 for singapore. etc. now i have a new provider, but prefix is different, how can i detect on lcr when all calls fail. i change prefix. i hope my question is clear sorry. regards, ron