You have to register a consequence for all possible results.
In your case:
LEAD -> MEET with result activity
LEAD -> FAIL without any new activity created
as I understand...
Then if you have a meet, new activity will be created, if it is a fail, nothing will be created, but you will be able to see the statistics, how much lead -> fails you have vs lead -> meet.

p.s. usually, when implementing this kind of consequences, we are defining more possible results, like "recall", "on ice" etc. with delayed activities created afterwards - after a week to call again, after a month to call again etc. Depends on the process.