Ability to Prevent Purchase of Individual Memberships when on an Active Family Membership

Our club is having issues with people selecting individual memberships that are "trumping" the rights of Family Memberships. We would ideally like to have a setting that prevents players from selecting individual memberships on the member portal if they already have a Family Membership assigned. 

Will work if it's a global setting (restricts all individual memberships) or if we can pick which ones to restrict that is good.