How to delete a record

[Tony Williams]

I have a database with three tables as follows
Table 1=Documents
Table 2= Groups
On a form based on Table 1 is a continuous subfrom that has a combo box
based on Table 2
When the user makes a selection in the combo box the selection is saved in a
third table Table 3
The user can make any number of selections of the combo box hence the reason
for a continuous form
If the user later deletes the value of a combo box for any record in Table 1
then the control stays empty and I end up with a blank record in Table 3.

What I want to do is if the user deletes a value in the combo box I want to
delete that record in Table 3

I hope that's explained what I am trying to do BUT how do I do it?

TIA
Tony Williams