Help with related forms

[jkfeagle]

I have a form (data entry setting-yes) with several tab control-grouped forms. All the forms/underlying tables are linked by a field called ID. When I enter data in the main form, related records are only created in the tables for the subforms if data is actually typed into them as well. How do I force the tables to enter a record in the subforms' table, when only entering data in the main form even if the only field with data is the ID??