You can't. On S12XE you can change priority level of each interrupt. On older S12 you could rise priority of only one interrupt using HPRIO register. On S12G you have no option to change interrupt priority. But do you really need it? HPRIO didn't make a lot of sense, since it applies to quite rare case when two or more interrupts happen at (almost) exactly the same time. What if lower priority interrupt happens just a couple of bus cycles prior to your high priority interrupt? No magic, lower priority interrupt executes first without interruption. So what HPRIO is supposed to solve?
