Entity mask command

I try to create a command to hide all entity under selected entity. so this is my result

It can effected to: Polyline, Circle, ellipse, arc and simple Block

Please tell me is there a way to change "ACAD_WIPEOUT_VARS" value in NOD to show/hide wipeout using .NET?

I have to use lisp in this project.

Thank for all your comments.

p/s:

It has two command:

EMASK : Add mask to entity

EUNMASK : Remove mask from masked entity

Download Here