I can't judge the pot size from the picture nor can I tell whether they're Oriental, Asiatic, or other but I'd assume Asiatic if I were to guess. Might be a good idea run a tool along the inside edge of the pot and loosen it up and gently ease the contents out and again, gently sift through the soil with your fingers to find the primary bulbs and their offspring and either repot all to a larger pot or individual pots. Of course I'm guessing that they're all the same variety in which case I'd try to keep them together. I've ground planted Orientals and Asiatic lilies in spring and early summer with no ill effects but it's likely not always the preferred method. I've found them to be reasonably sturdy plants in my growing zone. You'll find plenty of info here. For me drainage has always been key in maintaining healthy lily bulbs. The three that look alike are all good, that leafy one won't amount to much anytime soon but it's leaves are feeding a growing bulb.
Best of luck!
