We who don't have root authority are not super user.
We, who don't have root authority, are not super userS (As StoneyB suggests).
However, there are dozens of way to tell this including those ones in the comments.
We are not super users, who have root authority (-Jim)
[Good to note Wichita Steve's comment as well. Are those both statements true? Or one depends on another? Or one restricts the fact of another? - this all is a matter of clarification].
Taking it further, another thing could be simply stating why aren't you super users.
We are not super users as we don't have root authority.