Rick,
Using SAS/OR , could write this ：

data Units;
input Cholesterol @@;
n+1;
cards;
0.4 1.0 1.2 1.7 2.6 2.7
;
run;

proc optmodel;
set N;
num a{N} ;
num half_sum;
read data Units into N=[n] a=Cholesterol;

var X{N} binary;
half_sum=sum{ID in N} a[ID]/2;
con sum{ID in N} a[ID]*X[ID] = half_sum;

solve with clp / findallsolns;
create data out from [s ID]={s in 1.._NSOL_, ID in N: X[ID].sol[s] > 0.5} a=a[ID];
quit;

proc print data=out;run;