Can you wait until after they bloom? Most iris - bulbous (Dutch or reticulated), rhizomatous (Iris germanica and hybrids, aka bearded iris) or just fleshy rooted (Siberians, Japanese) - are liable to have their bloom sequence altered if you do it at this time of year.

If you can't, they will still transplant perfectly well but you may skip or reduce this year's bloom cycle.

Actually, that would be even easier. Thanks!