Research on the identification of the prosodic structure of languages has been based on phonetic processes, such as durational patterns and sandhi phenomena. One of the main assumptions is that such processes all signal, and are thus regulated by, the same structure. The experiment reported here tests the validity of this assumption by investigating whether prosodic boundary strength has the same effect on various segmental processes. The application of pre- and post-boundary duration and of vowel hiatus is investigated under different prosodic conditions in Modern Greek. Preliminary results suggest that there is a tendency for a similar effect of boundary strength on both processes, with vowel hiatus showing potentially a different application in one of the conditions.