Some problem about settings--CFX
 

"Equations are given two labels: the individual name and a combined
name used for combining residuals together. Residuals for multidomain
problems are combined provided the domains are connected together and
have the same domain type (solid or fluid/porous). If there are
multiple groups of the same domain type, then the group residual is
identified by the name of the first domain in the connected group. "



I have defined several domains of fluid types, and connected them with the method of "interface".
But however can I choose the specfic one to be calculated in CFX-SOLVER? Or all the domains have to be set?