I don’t think this is possible, but I would like to see srand2(), and u2() and so forth. srand() would only affect u(), and srand2() would only affect u2().
This means setting different seeds with different random generator. A quick search reveals that srandn() where n is number from 2-9, and they don’t exist and neither does u2…u9.
EDIT: I tested srand(n) inside math parser, and random values on different image. Seem to give me what I want. This’ll do.