Hi,
S32G platform integrates an Extended Resource Domain Controller (XRDC) which "provides resource isolations at the SoC level" [AN13024 - S32G Extended Resource Domain Controller (XRDC), Page 1, Rev 1, 03/2021].
The AN13024 describes more in depth this module, it can be obtained from the S32G2 product page (link: S32G2 Safe and Secure Vehicle Network Processor | NXP Semiconductors). This controller creates domains which can isolate resources from one core to another, or give permission to access it if needed.
As for running 3 cores with different applications, this is feasible under the S32G platform. There is the AN13750 (also available on the S32G2 product page) which details how to run the 3 M7 cores with a different application.
Please, let us know.