How to filter the entities by group name in Autocad?

How to filter the entities by group name in Autocad?

I need to filter the entities from model space by group name.Can any one
help me?
below i mentioned my code
i am mentioned the layer name wise filter
short[] ftype = new short[1];
object[] fdata = new obj[1];
ftype[0] = 8; // what value i need to put here for group Name this is
for layname
fdata[0] = "layName"; // my group name
AcadSelectionSet selset = thisdrawing.SelectionSets.Add("Selset");
selset.Select(AcSelect.acSelectionSetAll, null, null, ftype, fdata);
but i need to filter by group name. what value i need to put for ftype[0]=
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