Adding a second Subform to a Form in Access

I have a form with a subform and now realize I need another subform (based on a query). One table is called cases and the other is called documents. There is a one to many relationship between cases and documents. Then I have another table called scenarios and a many-to-many relationship between cases and scenarios (so I have another table called casescenarios). I have created that relationship.

I now need to be able to include a subform to the main form that will allow me to enter the scenarios for the particular case. I have tried dragging and dropping a subform into the main form, but it doesn't appear to be recognizing the relationship between the form and the subform.

Any guidance would be greatly appreciated!

Well I eventually got it to work - although it was quite a challenge. I created the subform separately, and the trick was having the rowsource and the column source differ (I used a listbox, which listed the scenarios). Then I dropped the subform into the form and added the linkchild, linkmaster info.