C# make a tab in checklistbox

I try to make a "tab" so a space between the limit of my CheckBoxList and my CheckBox to create a "menu" with sub-category like that :

CheckBox1ofMyCheckBoxList
         CheckBoxOption1ofCheckBox1
         CheckBoxOption2ofCheckBox1
CheckBox2ofMyCheckBoxList
         CheckBoxOption1ofCheckBox2
         CheckBoxOption2ofCheckBox2

Somebody have an idea to do this?

Thank you !