There is a variable named
BelleorElena that indicates whose path you are on. As of v0.60, if that variable ia greater than 5, you can only do things with Elena. If, however, it is less than -5, you can only do things with Belle. The result is that if (<5
BelleorElena > -5), you get both of them.
That variable may not be used in the future, however. In v0.65, the test is whether or not your MC has already had sex with Elena. If you did, you can have sex with her again. This makes it a lot easier for the developer to code, and for us to play. We'll see how that plays out in the next release, which looks to feature Belle.
To navigate that properly, you might need to use the mod by
KoGa3. Zoey Raven's walkthrough would have done the job, but he discontinued it after v0.20. It could be used up through then, though.
By the way, for anyone who is playing a Belle-only route, this release will be VERY short.