If you are a fairly new player, and you are running a particular quest in order to get a particular item, please tell the other players. It helps if you mention it early on; something like, "I'm hoping to find the XYZ item."
The reason you may want to do this is because, especially if you have several multi-TR's in the group, the item you are specifically looking for because it is a big improvement over what you are currently using/carrying, is likely vendor trash to the multi-TR. If you ask for it someone will probably pass it to you without a second thought. The reason I suggest you mention it early is because when a player is running that quest for the 100th time he is probably just going to hit "loot" on all the chests unless someone specifically mentions they are looking for something.
If the item is BtC or BtA, you're out of luck after everyone loots the chest. But if you ask politely at the start of the quest or before we hit the chest, the odds are you will be passed the item. In Servants of the Overlord today, a new player asked for the Darkstorm Helm in the locked chest and got four of them passed to him. He was absolutely thrilled and thanked us all a bunch of times, whereas me and the other three guys who passed them were just going to vendor the helms without a thought.