[syslinux] Is it possible to chainload isolinux.bin file from syslinux

[Z C]

I have a USB disk with syslinux files installed in /boot/syslinux, and the
bootloader is installed into MBR or VBR

I then extracted a *.iso file which uses syslinux as the bootloader, into
root dir of the disk. The iso file contains a rescue OS or an OS installer.
Now I got the directory /isolinux with files isolinux.bin and isolinux.cfg
in this folder

I can now boot into syslinux, but *what to do to boot/chainload the
isolinux.bin file to launch the OS*?

Note that just load the isolinux config file /isolinux/ioslinux.cfg (using
"config" module) instead of chainloading entire isolinux is not what I
want. Because the version of my syslinux (official compiled binary) and the
isolinux (from another verdor) may be different and the isolinux may
contain some 3rd party patches. So just load the config file will sometimes
result in failure.

My final purpose is to make a universal USB boot disk: It can boot any
extracted iso as long as the iso file is made using isolinux.

So perhaps the most elegant solution to this is chainload isolinux from
syslinux.

Thanks!