Yes, it may be that they were part of the same group. The reports are unclear on those details.
I suppose those armchair adventurers who have never seen wild country in winter, and especially avalanche country, can't fully appreciate the risk vs. reward that factors into such trips.
Personally, I understand and accept the controlled risk (and degrees of uncontrolled risk) of going into wild places. Generally, it's more dangerous to drive to these places on the highway than it is to go into them. And make no mistake: high country in winter is absolutely magnificent to see.
But the avalanche hazard ups the ante. It certainly scares the living hell out of me. I have seen the aftermath of full-bore alpine avalanches. Mature pine and spruce are ground up to pieces the size of your thumbnail. The resulting snow sets up like reinforced concrete.
And at the risk of being insensitive, it has been my experience that snowmobilers tend to risk more than self-propelled skiers and snowshoers. Perhaps that's not fair; I certainly can't prove it as a trend across the board. Speed can certainly get you out of dangerous zones more quickly; but you can't listen to the boom and crackle of the snowpack as you approach those zones, and 'group momentum' can take you places you would be loathe to enter on your own. In other words, the machine and the sport can overtake caution.
But I don't know if that's applicable in this situation. It's just my 2-cents' worth.