Rick,
ANY() also can do the same as ELEMENT() did, but need help from "OR operator" or "EXPANDGRID()" :

proc iml;
x= "A":"Z";
y={'0' 'S'};
test=expandgrid(x,y);
if any(test[,1]=test[,2]) then print 'At least one of Y values is in X';
else print 'All of Y values are not in X';
quit;

proc iml;
x= "A":"Z";
if any(x='0')|any(x='S') then print 'At least one of Y values is in X';
else print 'All of Y values are not in X';
quit;