For anyone interested, the quick and dirty hack to prevent a specific forum's daily topics from being posted to Today's Active Topics is to do the following:
### open ubb_lib_posting.cgi
### find &WriteHashToFile
### add before: (where FORUM_NUM is forum number, ie: 1,2,3,etc...)
unless ($_[0] =~ m/FORUM_NUM/) {
### add line after &WriteHashToFile
}
example:
unless ($_[0] =~ m/2/) {
&WriteHashToFile("$vars_config{NonCGIPath}/cache-$cache_cookie/s
earch_index/daily_index-$GotTime{LastLoginJulianDATE}-main.cgi", "daily_date_tim
e", %daily_date_time);
}