A .ses files

While AATranslator is great for converting to any other format, the best solution for converting ses files to sesx files is the purpose built ses2sesx 

Since Audition's session files are unique to Audition, I'm afraid that the answer is, inevitably, no. The only alternative is to  purchase SuiteSpot's AAtranslator, in which case you can convert them to a format suitable for any other software it will convert to, and that you have access to.

AAtranslator