Hello ,
I agree with , this question seem different enough to warrant a new question. However, I do have a couple of quick suggestions/reading material for you to look over that may be able to help you out.
Custom depth:
in-unreal-4/
Opacity Material:
If neither of these links provide you with a solution or the means to produce one please start up a new question and post a link here and I will be more than happy to assist you further.
Make it a great day