a related field will only return the firts created one Titles::TitleName, hence the title of the firts created related record in Titles.
What you want is achived by that
List (Titles::TitleName) this will return all the titles
so you'll get a vlaue list like that
Qi Gong for Seniors
Which wont help you much because your if will faill
then take a look at the filter function
Specifically, the FilterValues function which can compare a value to a list of values and return what, if anything matches.