You can however register different cards with different programs. If you go to one of the restaurants more than once a month, just use a different card each time.
Last night I called the AAdvantage Dining automated listing. Few of the restaurants I have been going to were listed. For instance, only three restaurants in downtown DC were listed. The 11/00 - 1/01 directory listed eight restaurants in that area. The same was true for Arlington, Virginia.
I hope that was only a glitch in the automated system. However, the system had been pretty reliable in the past.