How to make fragments stick together until force is applied in MassFX?

I’m trying to simulate the destruction of a building by first fragmenting the asset in to thousands of smaller parts with FractureVoronoi and later using MassFX to collapse the structure. My big issue with the resulting animation is that even though I destroy the structure at the base, the moment the building starts to crumble every single piece becomes loose and it looks like it “pulverizes” more than actually being destroyed as it reaches the ground. I can’t find any way to keep the top pieces (which are far away from the ground impact) to conserve some level of structural integrity.

I’ve tried applying a lot friction and this does not help. Overriding sleep settings don’t seem to have any effect either. Essentially I need fragments to stick together until a certain amount of force breaks them apart. I’ve been looking at constraints, but I don’t see how this could be applied at such a large scale with thousands of individual pieces. Didn’t this option use to exist in Reactor? It doesn’t look like this feature is built in to MassFX. :-(

Here’s a video of what I’m trying to achieve (on a much more basic level):

https://www.youtube.com/watch?v=J15bV4vMoM0
(Top of the building retains its form before crumbling down when it reaches the surface).

MassFX version I’m using: 3.4

Thanks!