If there are a group of 3 orcs (not henchmen) at close range and one of the PC's attacks an orc, is he in an engagement with all the orcs or just the one he attacked? I think he was using an action ( he was playing the Swordmaster) that affected other enemies in the same engagement. I looked for any rules concerning this and didn't find any. I told him at the time that he attacked one orc and he didn't attack all of them so he wasn't in an engagement with all them.

but, I was thinking how can you get involved in a multiple enemy engagement if I follow my rules.

Also, if another PC were to attack the same 3 orcs and picks a different orc would he be in a separate engagement or the same one as the first PC.

Would the rules change if the orcs were al henchmen?

It may be easier if you think of how you would do this using miniatures or standups for each individual. If they are in base to base contact, they are engaged, otherwise they are not. So, if the 3 Orcs are all separated from one another when a PC engages one, he is not engaged with any of the others. If a second PC engages a second Orc, he is not engaged with either of the other Orcs or the other PC. If the 3rd Orc then moves into base to base contact with either of the PCs, he joins the respective engagement, so you'd end up with 2 Orcs and 1 PC in one engagement and 1 PC and the remaining Orc in another engagement.

Henchmen move, act, and are tracked as one, so if a PC engages one, he is engaged with all of them. Henchmen make one attack roll with a Fortune die for each additional Henchman in the group. When wounds are applied, they all go against one Henchman until he receives enough to remove him and any remaining wounds carry over to the next and so on. For each Henchman removed, the Henchmen's next attack roll loses a Fortune die. So in most cases it doesn't matter whether you represent Henchmen with individual figures or just one that represents the group.

To echo what mac40k had said, it depends on the initial status of the orcs. Are the three orcs engaged with each other?

If one orc has some tasty elf ears, are the other two orcs close enough to rip them out of his hands? If an orc gets his elf ears stolen, is he close enough to tear the arm off of the thief? If the answer is yes, then the orcs are engaged with each other.

If the orcs are engaged with each other, and your PC engages with one of them, he is now in an engagement with all three orcs.