I have trouble dealing with groups.
When everyone is in the same moods things go smoothly (though sometimes I fear to disturb), but if you have different types of people to handle at one time things get complicated.
Have you ever been in that situation where you just know somebody in a group doesn't want you here ? How do you handle him/her if you need to speak to the person he/she is speaking to ?
Ever tried to seduce a girl in a group ? Do you go straight to the girl ? Do you speak to the group only (if so how do you use body language, targeted to one person, switching between everyone) ? What if another girl is interested in you (or another man interested in the girl) ?
Ever tried to sell something to a group ? If your targeted person doesn't respond, let's say the IT manager, because he had problems in the morning and is still thinking about them, what do you do ? Do you hope his body language doesn't reflect his attention level and just continue or do you switch to another target ? If you switch, to whom ? the most useful person or the most trusted person in the room ? If it is the must trusted person, how do you identify him/her ? Do you ditch the powerpoint at one point and start to improvise?
Ever taught something to a group ? How can you make sure everyone understood when you deal with more than 20 people ? You could of course go for the average people (take the least engaged and the most engaged and go with it), you could look at everyone, one after the other. Not sure how to be efficient though.
If you have a one upper and a tank in a group, could be explosive, what do you do (without getting them in separated rooms) ? If this is a one upper and a passive, how do you get the passive to speak and act ? Those situations shouldn't be happening if teams were built properly but sometimes you just have to deal with it.
Those are examples, but there are many situations when you have a disturbing element to handle in a group. Particularly at work. I would be interested in knowing what body language can do when you need to send different signals to different people that you can't isolate from one another easily. Anything on group interaction would be great too, there are many interesting things like conformism, bystander effect... Those are not directly related to body language, but creating a situation isn't it non-verbal communication after all ?