Method needed to identify Contacts that are not valid from the Comp Screen

Question

Problem
My Company has 65k contacts in the system, we do not delete contacts that are no longer at company, as when we buy data our data in some cases will be more up to date that the third party data available on the market. This then means when a user looks at a company record and the related contacts, he has to hover the cusor over each of the contacts to check if they are valid or not.
Goal
When a user looks at the contacts linked to the company the following fields will be presnt:
Contact Valid
Contact Leave Date.
This will then mean the user will be able to see without looking which contacts are valid and which are not.
Problems
I have tried to create a contact page layout with the fields needed however the only fields avaiable are as follows:
Company ID
Company Name
Company Status
Contact ID
Contact Name
Contact Roles
Location
Primary
Can anybody help?

Answer 1

Thanks for the reply.
However I think I didn't make myself clear in my post in terms of the problem. The problem I have is that when a user looks at a company (account) record the user see the following information in relation to which of the available contacts to select "Primary,Last & First name,Job Title, Contact Role, Work Phone and Email". However none of these fields show if the contact is valid or if they have a leave date.
Both Contact Valid and Contact Leave date have been set up in the system within the contact record. I want to change the layout and have spent hours in the following screens and functions.
Page layout Management
Company/Contact Related Information layout
Related Information Setup
Company/Contact page layout
The problem is the screens/functions where I think I could add the two above mentioned fields end up with me turning the fileds into required or read only fields, and the section where I want to drag in the fields to display has the two fields missing.