If you create a new Analysis Module with a Keyword search.
In this Keyword search ypou are searching for seceral words and each word does have a match score.
word1 Matchscore 1
word2 Matchscore 1
word3 Matchscore 1
word4 Matchscore 1
the thresold score for this analysis obeject is 3.
the Mail must contain at least 3 of these words before the analysis Module match and block the mail.