Allow Two or Multiple Names for one shared Email

We have the same issue for our financial services client. A father buys a financial plan - which is eligible for his wife and his son - they are on the same plan.

As they have the same email not able to associate the wife and son to this financial plan.

Each person as a unique ID but the same email.

What do you recommend?

As it is rather urgent - for an enterprise HubSpot account