Group + subgroups

Hello,
i do not know if this was post before.

can it be addedd the option to add subgroups¿?

i have now problem with big company which has diferent companies like

Company A
company B
company C
company D
  subcompany D-1
  subcompany D-2
  Subcompany D-3

How do I make this in groups?

thanks

regards