Possible to mutli boot another ISO?

Hello all,
Thank you for a great application, 

I would like to boot winpe and other OSes. but Im doing something wrong and
cannot figure out what it is.   

I downloaded the latest Winpe available, did all updates.
I am trying to multiboot WinPe and another .ISOs.
I set the boot manager to Grub4Dos and the skin is the GFX-BootMenu and saved.
Open OtherOSY
Check to Enable ISO image
Navigate to select the iso.

I build and install to the USB.
I boot up but the boot menu is not asking me to select a different OS, it just loads as a regular Winpe install.
The winpe works as expected so I know I am building the images correctly.
I searched the forums but can only see a couple of topics that are similar but not what I am looking to do.
Can someone point me in the right direction? pleeeeze.

Check out http://www.easy2boot.com/ I have used it for years and boot several different flavors of PE, 32 and 64 bit as well as a Few Linux and utility ISOs, all from the same USB drives.  It works on HDD as well. 

Hi RabidFangs
Haven't used ISOImages since win81 when i used it regularly
so just tested it on a Win10PESE build, it works for me, tho I cant remember how to adjust the menu timeout in grub4dos,
so you have to be quick with the down arrow or it boots to the default image, but if you can I can confirm , it does boot multiple iso's

available at
http://w7pese.cwcodes.net/projectindex.php    --->  Win7PESE/OtherOS/ISOimages

Edit
btw   I know this is a very old post (just in case someone comes across it)
but you adjust the grub4dos menu timeout on the Create ISO plugin on the timeout dropdown

A related problem with multiboot is if the USB was formatted Fat32 or NTFS. If i run MediCat and Sergei their W10-PE on fat32, then i do not see the first boot menu, and the isos disrupt the other boot cds. So then i format the USB to NTFS and there you go. No errors and i see boot menu i never saw before. So it could help to format your drive from fat32 to NTFS if you have booting problems. Simple test and can save you hours of looking for a solution to why the boot menu does not come up. ;)

One easy way to multi-boot is to use AIOBoot.

www.aioboot.com