Sure of course it's possible.. if the iso's are small enough.. which seems doubtful to me. You'd do it the same way as you would on a dvd.
Generally for multi game discs, if what you have are isos.. you'd have to extract the actual files out first to start (You can use XISO or xdfsextract.exe). Then you'd have to put the respective games or emus into their own directory (each with their default.xbe in that dir root). Then you'd use some menu program like MENU-X or similar as a disc front end launcher. I've seen some people even use Evox as a multi-game-disc launch menu which of course will work fine. Anyway, either of these require some configuration which I won't go into here.
Then after that.. make it into a nice bootable GDF Image (using xiso again, or gdfimage.exe, etc.) then burn and voila
But why would you want to burn 2 iso's on a cd? Just burn them on seperate cd's.. cd's are cheap enough

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