When modifiers and materials are assigned to family elements that are imported or linked to 3ds Max, they propagate throughout all instances of the element if their family and type match exactly.

For example, one particular part of your model shows a room with three doors. Two of the doors are Doors <Single-Flush : 32” x 80”> and the third is a Doors <Single-Flush : 36” x 80”>. If you change the panel material of one of the Doors <Single-Flush : 32” x 80”> doors, the panel of the other Doors <Single-Flush : 32” x 80”> door will also change because their family, Doors, and type, Single-Flush : 32” x 80”, are identical.

Propagation of materials can be controlled by toggling Propagate Materials To Instances.