LEM Rule Correlations – Group vs. Individual

All,

I am starting to create rules for events and I would like to be as efficient as possible.  I noticed it is possible to create a LEM Rule with a Group Correlations.  However, I am not sure of the differences between creating a LEM Rule with a Group or an Individual correlation.  I read a post by curtisi which mentions creating a Group reduces the resource requirements.

1. Does a LEM Rule with a Group Correlation mean “match all conditions” before the action is taken?

Any assistance would greatly be appreciated.

T.J.