Pre-Coloring Constraints

In the Constraint Manager constraint view, set the following in the Within Group for the net class that contains the critical nets:

Spacing constraints and/or pre-coloring spacing constraint groups
Same Mask pre-coloring constraint true specifies that all the shapes for the nets in the net class must be on the same mask for each routing layer.
(optional) Mask Name ensures that shapes will be on the specified color mask for each routing layer for the nets in the net class.