[R] Spearman's Rho Help!

[Suresh Kumar Karanam]

Hi,
I have a dataset with four categories of data, the number of samples are not 
the same in each category. I want to find the Spearaman's Rho. Let me give 
an example.
x=(14.22770439,26.49420624,46.7277932,19.02550707,23.37379361,16.97789862,19.77100085,23.11270162,13.72929843,33.54430621,14.4756979,70.15811106,11.22789833,NA,NA,NA)
y=(143.2420241,45.24260203,62.13218994,27.79050219,27.41029595,191.2759927,141.1430225,234.1600259,37.69120463,156.332942,19.98579421,34.77930022,69.90888888,21.92539608,NA,NA)
z=(70.28027834,349.7838817,29.81811184,83.48042267,52.47989761,107.7110162,71.24609317,155.6580091,68.37158664,156.3179887,134.8930305,80.25242044,100.5309559,266.4470408,65.4934171,22.86950128)
v=(150.2099947,73.52000706,83.18122348,150.3240468,352.9101222,195.8919089,263.9489287,114.2090369,153.5000165,18.62309563,117.2399949,441.8981252,285.3369951,161.3959985,NA,NA)

I want to find the spearman's rho for this data. To my knowledge spearman's 
rho is for x vs. y or x vs. z or any combination. Is there a spearman's rho 
for the data all together (x y z v)? Please help!
Thanks a bunch.
suresh