I would try it. Alliums as a rule take well to transplanting. What you might lose due to transplant shock you will more than make up due to the plants having more growing room. You might get small bulbs this year, but they should size up when you replant for next year. The other option would be to wait until they mature and harvest all the little bulbs, which might all be singles. You'll probably get fewer that way, but still have decent planting stock.

My masses of volunteers are in an area beyond the garden where I've thrown out shriveled bulbs. This time of year I dig clumps and eat them like g'allions (garlic scallions).

They plants will grow if you dig a clump and transplant the ones that come away with roots attached, but they won't make big bulbs in my experience.