Good morning.
Long story short:
Is it GRUB2 capable of chainloading directly an isolinux.bin file (sort of stage2 for the iso bootloader of syslinux bootloaders project)?
P.S.
I know I can chainload unextracted iso directly by loopback device, but I'd rather like be able to use original distro boot menu, with no need to manipulate any config file.
Long explanation for bored people with some spare time:
I'm setting up a multiboot usb thumbdrive, just systemrescuecd and kali linux at the moment. I installed GRUB2 on MBR and on a separate /boot partition. Then I created two more partitions where I extracted the content of the two iso distros. I didn't execute their persistent installation scripts, beacuase I think that the only tasks they execute are unpacking the iso and install a syslinux bootloader. Considering that the isos themselves already ship an isolinux complete configuration (isolinux.bin, isolinux.cfg, etc.) I'd like to chainload directly grub to that.