I created a relationship that links an object to another object .
My scenario goes in this way:
If a user select an account using the lookup search functionality and also wants to search for contact related to that account only by using the lookup funcationality. What validation rules can I use to create the linkage to only have the contact related to that account searched for by using the lookup tool.

Thanks.

Has anyone completed this trail? I am stomped on challenge number 3, regarding created the process for fulfillment. Any pointers or guidance would be appreciated.