Just a missing hint which you can report next time you see this sentence.
Possession can be marked by putting the possessor in front, so (I think) a titkárnők könyve would be "the book of the secretaries; the secretaries' book".
But that's not how a titkárnők is used in this sentence, of course.
a titkárnők has as a phrase hint "... of the secretaries". (And only that, not also one that says "the secretaries". The individual words a and titkárnők have word hints which appear further down, of course.)
OK, got it now, thanks! Yes, that's it:
"A titkárnők munkája" - "The work of the secretaries".