[Help?] Tips on Solidifying/'Static'-ifying models with multiple parts in NifSkope

[Pitdeggeh]

To put this very simple, I'm attempting to 'seal' the Power Armor helmets included in the Vanilla game of Fallout 4, where there's two pieces by default (for the frame to open)

 

As you can see, Exhibit A

 

There is a problem with this. I am not amazing at NifSkope, infact, I know basically nothing about NifSkope. Some help getting that back part to snap into place and stay there, essentially becoming 'part of the model' similar to how it used to be in Fallout 3 and New Vegas; a whole helmet instead of a helmet in two parts, would be very much so appreciated.

 

Some assistance here would be swell, and much so appreciated! If you want my Discord or Steam to walk me through this/ask questions in a more timely manner, shoot me a PM. I'll be checking on the daily.