I guess my question is are the sub forms returning information related to anything in the parent from, or are these used to also enter data. Without knowing more about your specific needs its hard to place a solution. The sub forms are objects just as much as the parent form. This means that they will have their own properties and settings that are separate from the parent from. You can try several things, but again, without knowing more about the sub forms role, it will be difficult to ascertain your needs.
1. Highlight the form in design view and press F4 to view the properties window for the sub form.
2. Design your sub form as a stand alone form and set the properties as you wish. Any changes made to that form will cascade up to the sub form copy. Then use the wizard on your main forms tool bar and select add sub form. From the wizard, select use current existing form, and select the form you are after.
3. If the sub form is taking data, I would suggest using the After Update Event and/or Lost Focus Event for the sub form and set the enabled property to false.
I hope this helps. I'll check on you in a few days. Let me know if I can help more.