Multiple Partitions Support of one Physical eMMC. One partition exposed to USB, one hidden only for the STM32 to write files

I have an eMMC using File System Component  Version 8.0.2 and USB Component  Version 8.0.1 i see the filesystem on my computer, can write and read files.However i would like to have something like

fsStat = fformat("M0:", "/FAT32", size_part_0, "M1", "/FAT32", size_part_1 );

which allows me to mount M0 and M1 and use file operations on both partitions. Also only one partition should be exposed via USB.

Im aware that "Multiple partitions are not supported and will not be detected."

But is there a workaround (I prefer to not port FatFs because using FatFs with the keil MDK USB seems not trivial)?

BR Raphael Zingg