Adding a joist to make it a double joist across beam

by Bret
(Kansas City, MO, USA)

I want to center a hot tub over a deck beam sitting on concrete pillars. A structural engineer has suggested adding a joist to make it a double joist in the area the hot tub is placed.

My question is can I add the double joist centered over the beam and just screw (or carriage bolt) it to the original deck without connecting it to the ledger board on the house? I need to double up on the joist for about 10' or 5 ft on each side of the beam.