BP Group Hierarchy - CRM 4.0

Hi Experts

Please help. I have set up my hierarchy as follows:

Group Level

-

Node 1

-

BP 1

-

BP 2

Is it possible to assign a BP number to Node 1? If so, how do I do it? Alternatively can I assign as follows and if yes, how?

Group Level

-

BP 1

-

BP 2

-

BP 3