C-MAP USA does have a program for Club C-MAP members who require
duplicate
C-card, and NT/PC chart coverage like the situation you are
describing. You should contact our Customer Care Department at
1.800.424.2627 for the specifics.

Also the following link will provide information on Club C-MAP.
http://www.c-map.com/clubcmap/Clubcmaphome.asp

J.McQuade
C-MAP/USA