I need to count number of consequtive weeks within a group:

 

Group_name                                                consequtive: 2

         person1                                             7/5/07

         person2                                             7/19/07

         person3                                             7/26/07

 

 

Consequtive is equal to 2 within this group, since person 2 and 3 are 1 week apart.

 

anybody know how to code this in CR XI?

 

thx in advance