I am just curious as to how in many games (namely games like arkham asylum/city, manhunt, hitman) do they make it so that your character can "grab" a character in front of you and do stuff to them. I know this may sound very confusing but for an example go to youtube and search "hitman executions", and the first video is an example of what i'm asking.

Basically I'm wondering how they make your model dynamically interact with whatever other model you come across, so in hitman when you come up behind some one with the fibre wire you strangle the other character or if you have the anesthetic you come up behind some person and put your hand over there mouth while they struggle and slowly go to the floor where you lay them down. I am confused as to whether it was animated to use two models using specific bone/skeletal identifiers, if it is just two completely separate animations that are played at the correct time to make it look like they are actually interacting or something else all together.

I am not an animator so i assume most of what i just said is not right but i hope that some one can understand what i mean and provide an answer.

PS) I am a programmer and I am in the process of building a hitmanesque game, just because i love that style of game and I want to increase my skills on something fun, so if you do know what i'm talking about have some examples with involving both models and programming (i use c++ and mainly Ogre3D at the moment but i am getting into unity and XNA) i would greatly appreciate it.

Thanks.