in brief... the global sampling values in your render options are always
the limits for your per-object sample values. (further restrictions can be
applied with another couple of sample values in the options block
specifing an inner valid range.. not available here, you'll never use it)


this means that if you have a global sampling of ie -2, 1
your per-object sampling should be in that range.. like with a 0,1.


that said, if for example you low down the max global sample value to 0..
also the max per-object sample will be raised to 0 if bigger.. thus obtaing
here an uniform sampling (0,0) as you can see in the diagnostic mode.

same here.. if I try to supply a per-obj min sampling value minor than
-1, that's the global value, it will discarded and used instead the global one.

put in a scene a geometryprimitive. load the ctrl_selalias..
add the object (multiple objects are supported).
put another geoctrl_selalias if you need another group of
objs with a different custom aa.