How to track history of dependents in the contact form?

Hi,

We have a requirement wherein history of dependents needs to be maintained.

Let's assume an EMP 1 has 5 dependents. All these dependents are captured in the contact form.

The employee is availing insurance and other facilities based on the number of dependents. Employee has to update after a particular period of time how many dependents are there so that correct  insurance amount can be paid to him/her.

Now consider for a particular period, two dependents are removed from the list for any reason (say they move out of the country) . How this can be maintained in the system ?

The system should consider only 3 dependents this time.  I know payout will happen via payroll and other FF can be developed for considering these.