Wandering Monsters Loot Probability

Hi everyone!

I have a pretty straightforward question concerning the following phrasing:

"Wandering Monsters have only a 50% chance of carrying treasure. They are poor sources of XP and valuables!"

Now my question is whether I roll the 50:50 for every monster in an encounter (e.g., 3 goblins have a 50% chance of carrying a small treasure each of LVL 1), or do I roll one collective roll (in that example 3 goblins have a 50% chance to roll once on the same treasure table).

Now the former would make sense to get a party more smaller trinkets and a better chance to get at least something, while the latter would give a chance to give stronger items earlier. In general I feel like a lot of the wording in shadowdark rules treats an encounter as "one monster" in terms of difficulty (e.g., by the 1:1 monsters table), so it would make sense to treat treasure the same way.

Let me know how you handle this, thanks!