Before I dive deep into this question with details, can I create a Form_B that has a Tab Control with sub-forms, and then on one of the Form_B Tab Control Pages have another Tab Control? Thanks
IIRC, there can be up to 7 levels, at least for subforms themselves. So a tab control could be inserted on each of those subforms to contain the next level subform down, up to the 7 overall limit.