[mx] : set depth

Is there anyway to set the depth of a mc, let’s say that I have:

mc_00.getDepth() = 100;
mc_01.getDepth() = 101;

mc_99.getDepth() = 199;

and I want to change their depth so that:

[changed] mc_00.getDepth() = [old] mc_00.getDepth() - 20;
[changed] mc_01.getDepth() = [old] mc_01.getDepth() - 20;

[changed] mc_99.getDepth() = [old] mc_01.getDepth() - 20;