I apologize for the title.. i couldn\'t find a better way to explain the situation.
I use to load properties file using a Property class as described in the URL http
Never seen that before. You could make your own preprocessor of course. As long as the referenced property occurs before any references to it, you should be able to implement it using some regular expressions/string replacement. But: I would not recommend this method.
Better resolve the duplication by defining different properties:
url.games={url.main}/games into url.games_extension=/gamesurl.main to url.games_extension to get the full games url in your application code.