please help!!!fluid zone problem

stk

hello to everybody ! i face a real serious problem to me and i unfortunately believe till now that fluent can't handle it! The problem is that i want to fix the VALUES IN A SUBDOMAIN OF A PARTICULAR FLUID ZONE (CELL ZONE) WITHOUT CREATING A NEW ONE BY SEPARATING CELLS. This will help me in a dynamic mesh problem, because if i have two separate cell zones, i am receiving soon the well known negative volumes message (fluent starts to move the "stationary" fluid zonein an unexpected manner)! thanks!