asterisk users - Jun 2004 - Excluding DIDs from telco long distance codes

I am having trouble excluding a range of DIDs from long distance account
codes setup by our telco.  Our telco (GCI) is dropping all callerid
information, sending out one number in place, which is what we have
requested.  They have done something to exclude the range on their side,
apparently independent of callerid.  Is there something I can do in the
dial-plan to tell Asterisk to send the telco the info they need to exclude
the DIDs from their ld codes?  Any suggestions or pointers to more info?

Thanks,

Josh