Active Directory bridgehead server

I am using a textbook which has two apparently conflicting statements:

First, “You can configure a preferred bridgehead server or multiple preferred bridgehead servers to control replication….”
Second (next paragraph), “Multiple bridgehead servers cannot be configured.”

The second could be a typo; however, the book is excellent and I wonder whether the authors had some context in mind. Do you have any ideas why/where both statements could be correct?