Perhaps you could apply the desired opposing impulse manually on hit, in a similar fashion to what was suggested here:
The math can be done much better, ofc - it was just an example. Some kind of curve would be nice, surely.
edit:
I am under the impression that the PMC overrides what the physical material is trying to do:
In which case (tested it only very briefly) you may need to either switch to your own physics sim, or apply the effect manually as suggested above.
Cool story, never realised the PMC vs just physics sim does that (Restitution
set to 0 and with Min Override
):
There, I learnt something today. Try something along the lines of:
With the restitution set to 0.5 - every contact halves the projectile velocity. Massage some values as needed, ofc. Also, even though there is no material assigned to other surfaces, a default is always provided, spitting out default values.