Grouping/Clustering results based on shared values
You could use the Jaccard distance to compare two jobs: i.e., the distance between two jobs is

$$d(A,B) = {|A \cap B| \over |A \cup B|},$$

where $A$ is the set of applicants for the first job and $B$ is the set of applicants for the second job.  Then, use any standard clustering algorithm with this distance measure.