You can use the information on this page:
http://msdn.microsoft.com/en-us/libr...ffice.10).aspx
. . . to help you to force the focus to go to the next sub form.
For instance, you can put VBA code in the 'On Lost Focus' Event of the last field on your first sub form telling Access that when you leave that field, you want the focus to go to the first field of the second sub form.
Your code in that event might look something like this:
Code:
Forms!MainForm.SecondSubForm!FirstFieldOnSecondSubForm.SetFocus
I hope this helps!