...
Various organizations may want to participate in peer to peer campaigns as a collective. For example, a university may want to participate in a peer to peer event and have a university wide fundraising goal but would encourage students to form teams within the university that would contribute toward that goal as well. This can be done in Engaging Networks using the Organizations functionality.
...
Go to P2P > Sites and edit the relevant site
Select Site Pages (under Building Blocks)
Edit the Registration Page
Select the Personal Details tab page of the registration pageform
Add the Organization Handling block
Within the Organization Handling block, select which Organization Types that should be available to supporters on your peer to peer site.
...