That's going to take some doing, mods in XSP work by overwriting files, and different mods can (and do) overwrite the same files.
I suppose that XSP could handle mods in the same why that Minecraft handles Resource packs though.
Attachment:
mod list.png [ 1.63 KiB | Viewed 14151 times ]
Mods that are disabled are ignored. Mods that are enabled are then loaded in order they are arranged. The mod creepy_dungeon_v0.2.zip is loaded first, and then it's v0.21 patch is loaded second because it overwrites some of the same files as the mod does with newer version. If the patch was loaded first, it would be meaningless because older versions of files would be overwriting newer ones.