subform for names

I have created two subforms
fron two tables; tblPlaintiff and tblDefend
subforms are in the main form "FMCase"
all are connected (relationship) by the CaseNo one-to-many
problem:
after entering the case number in the FMCase, the subforms,
PlaintiffSub and DefendSub both show the just entered case number.
Now I am in the subform Plaintiff and enter a first name field and last name field, this generates the case number, first name and last name in the TBLplaintiff
When i enter a second name, this generates a second record with the same case number in the table.
How can i have one record for case number and then a list of all of the names listed in that case number instead of seperate records for EACH name?

Did you create a data model (tables and relationships diagram)?
How did you represent Case, Plaintiff and Defendant?

Just to confirm - With Form/subform, the 1 side of your relationships is in Form and the many side is in the subform.

relationships:

cant figure out how to upload database

the relationship is CaseNo from tblCase to
PLCaseNo in tblPlaintiff
and !!
CaseNo from tblCase to DECaseNo in tblDefend

one to many connecting by CaseNo in each table