Just a note, I believe the word you are referring to is sempai...and personally, I tend to avoid it outside of a strictly Japanese context. Western society doesn't really allow for the development of the sempai / kohai relationship. It tends to become easy to abuse even in the Japanese context, let alone outside of it.
Sempai just means "Senior" a student that is higher ranked or has been there longer is just that... A senior student. It has no connotation of a relationship other than they are also learning, but have been around the block more than you. Why would you be squemish about using the Japanese term when you practice a Japanese marital art. Do you not use terms like Ireminage, shihonage, and jujinage in favor of terms like entering throw, four corner throw, and figure ten throw?
Secondly, how do you know what kind of relationship she has with her seniors? Just because she isn't Japanese doesn't mean she cannot relate. If that were true that one cannot understand a sempai relationship, can you honestly say that an American can understand a Sensei relationship... can one pass on any knowledge of Aikido without at least some knowledge of this relationship?