Yes there is a way...
There is a free program called WinAIO Maker Professional from JoshCellSoftwares
http://joshcellsoftwares.com/products/winaiomaker/
View attachment 11040
1. You will need to extract you x86 ISO to a folder (for example) named
Windowsx86 and do the same for x64 folder.
- So you will have two folders with extracted ISO's named Windowsx86 and Windowsx64
- You can extract the ISO's using 7zip or other favorite archiving software, or there are options to do that within the program itself, you will find an option "ISO2Folder"
2. Then the step 1 in the screenshot comes...
- Open WinAIO Maker Pro, and you will need to click on "Select Wim's"
- Navigate to the Windowsx86 folder and you will find a .wim file in the "sources" subfolder, select it
- Now again, do the same with Windowsx64 folder...
3. Save all changes like step 2 in the screenshot. It will show you that it has merged those setups into one
4. Now you will need to create a single ISO from those two. Just click "Save all into ISO" like step 3 in the screenshot and provide the destination where you want to save the ISO.
This will not guarantee that the final ISO will fit on a single DVD (it depends on the architecture, compression, and other things, in the past I was able to create a single Windows 8.1 Pro with both x86 and x64 setups and it had a weight of 4.35 GB, so it could fit on a single layer DVD, but like I said, it depends how many Windows Updates are already integrated into setups )
You can also, select the "Enable x64 Recovery Mode" in the left upper corner of the program so you can use recovery options from 64bit setup of the ISO. It could take more space but it's usefull
Enjoy