Hello @sg_cnh,
Thanks for reaching out to us. About your question, the IGMP is not a feature we can support in the S32G community, as far as I can tell the IGMP is done over IP, it is not related to the S32G itself, I checked the GMAC, PFE modules and the SJA1110 chip and none of them include direct support or examples for that feature. You may get some guidance in Other-NXP-Products, where the support engineers for the SJA1110 can help you.
I apologize for the inconveniences.