Regress on any non-missing scores

[mscbuck]

Hey all,

Is there a method that I can tell SAS to regress against any non-missing values in a series of variables? In my data set I'm using, each person has taken a pretest, and the name of the pretest and the score is linked to each observation. Now, the trouble is that there were 67 different tests that they could've taken, so each student usually only has 1 score linked, but a couple have 2,3, or 4 scores linked to them.

So for example, they may have data for score1, score37, score50, and the rest of the "score" variables are blank. Is there anyway I can tell SAS to regress against any non-missing values in the series score1-score67?