Possessives and Attributives

Q. If a phrase is possessive in the first instance it is used, is the abbreviation possessive as well? For example, should it be “Student Psychological Help Line’s (SPHL) 24/7 assistance center” or “Student Psychological Help Line’s (SPHL’s) 24/7 assistance center”? I know that you answered this question already. However, your answer was to avoid that type of phrase. In my case, I work for a company in which the possessive phrase, which gets abbreviated, is part of a larger phrase. (The above example is real.) Hence, I need to know what to do if you absolutely have to use this sort of wording.

A. If you can’t avoid it, you get to choose. You have the power! Use it well.