Hello Robert,
There is no switch in S32DS, which could be used for generating one .elf file or more .elf files. Creating one or more .elf files is mostly dependent on linker file.
But you can create new project and modify it on your own. Please look at the project in the attachment. It is simple example project which shows, how to modify necessary files. Example is created for MPC5748G, but it is usable for all MPC57xx family devices (with small changes). You can also find this file in S32DS(version 1.1) installation folder.
Regards,
Martin