How to add constraint to access bounded form.

Hi everybody .I created a bounded form that allows user to enter the following fields information
to the sql server db that is linked to access .The fields are: Projectno, taskcode, taskdiscription
and total hours worked.

I want for example when a user tries to enter total hours work for a user (Hours in hours worked table) and
if he did not already enter wages of the employee for that particular project (amount in hourly wages table)
that user get a massage prompt and ask user to enter amount in to hourly wages table first. Possibly opening that form.

I be happy if some one help me add this feature to my form. Thanks

http://i5.photobucket.com/albums/y18...constraint.jpg =====> table reletionships pic