r function for calculating extreme spread in group

I'm trying to figure out how to write a r function that will calculate  
the extreme spread of a group of points given their (x,y)  
coordinates.  Extreme Spread is the maximal Euclidean distance between  
two points in a group

ex.spread = max{ sqrt [ (xi-xj)^2 - (yi-yj)^2 ] } for i not equal to j

I have 60 levels to apply this to.

There is the combination function in the dprep package but I wasn't  
sure how to use this or apply an index the points in each group.

Any ideas?



Steve





Steven Matthew Anderson
AdAstra69 at mac.com

Ad Astra per Aspera