I suggest, (if you have some DSP available) to put in your chain the X IR you want as separate blocks.
I don't know if you can change IR with snapshot but even if you can , there will be a gap in the change due to the loading. That's not the idea with the snapshot functionality.
As contrary if you put 2 blocs and active/desactive the desired block with the snapshot functionality, you won't have this issue cause the 2 IR will be loaded at the preset selection.