The answer is...it depends. Are the other individuals on the Certificate as Joint owners or Beneficiaries?
If they are all joint owners, any one of them can take all of the money at any time (including while you are still alive.)
If they are beneficiares, unless you have specified differently with your bank, the funds should be divided into three equal shares.
_________________________
I can do all things through Him who gives me strength. (Phillipians 4:13)