[R] Clustering Question

[Kel Lam]

Hi group,

My case has N physicians with each seeing M patients. 
One physician could have seen a group of patients, or,
a patient could have been seen by multiple number of
physicians.  In order words, there are overlaps.  Now,
I have the following NxM matrix

              Patient#1 Patient#2 Patient#3 .......
Patient#m
Physician#1       1        0          1     .......   
 0
Physician#2       1        1          1     .......   
 1
Physician#3       0        1          0     .......   
 1
.                 .        .          .     .......   
 .       
.                 .        .          .     .......   
 .       
Physician#n       1        1          0     .......   
 0

"1" indicates previous encouter and "0" otherwise.  My
aim is to identify physician group practice based on
the common patients they see.  Any suggestion on which
R package would best serve this purpose?  Thank you so
much!

Regards,
Kelvin