[AccessD] Create subform record when form record is created

This question is for an event ticket sales application (with assigned
seating).
 
I have one main table (tblEvents) for the header information (name, date,
time, etc.).
 
I have three section tables (tblEventSectionLeft, tblEventSectionMiddle, and
tblEventSectionRight) for the ticket sales information. This was necessary
due to the number of fields required. This contains the status of each
auditorium seat (A=Available, R=Reserved, S=Sold). Each of the 3 section
tables is related to the main table, with referential integrity for cascade
update and cascade delete enforced.
 
Normal data entry using a form with three subforms works as expected.
 
I also have a report that includes main table information and 3 subreports.
 
My problem is that when I try to print a report but have not yet entered any
data in one or more of the section tables, I get error 2455. This is because
only main table (header) information has been entered; no section table
records exist. But, since all fields in each of the 3 related tables have
default values (they all default to "A"), my question is this -
 
How do I automatically create the 3 related section table records as soon as
a main table record exists?
 
As always, I appreciate any suggestions.
 
Best regards,
Bob Gajewski
 
P Please consider the environment before printing this e-mail