*GPMN::Database::Table::org::pre_insert =
*GPMN::Database::Table::user::pre_insert =
..... # repeat for another 15 tables and then do the same for ::pre_update

for (qw[org user group foo bar]) {
    no strict 'refs';
    *{"GPMN::Database::Table::${_}::pre_insert"} = sub ....
    *{"GPMN::Database::Table::${_}::pre_update"} = sub ....
}