When an InstallShield installation is built, a property called ISReleaseFlags is added to the Property table. This property contains all the release flags that are included in the build. This is great, because you sometimes what do create conditions based on release flags or write InstallScript code that only applies if a certain release flag is included in the release.
To access the ISReleaseFlags property, you can use MsiGetProperty(). Remember in InstallShield 2012, the behavior of this property was changed. Therefore, you must account for the new behavior. It is outlined in this Knowledge Base article
Here is an example with ISReleaseFlags using my version of the MsiGetProperty function:
Accessing ISReleaseFlags in InstallScript code
I have found this flag useful in my current project.