That requirement is what made this problem difficult for the devs to solve.
The issue is that knowing the offset of seeds helps predict outputs.
Instead of calling RNG(seed+hash(string)) 10x, make one RNG(seed) and call that 10 times to get random seeds for your 10 rngs. Now you have perfect determinism and no correlation.
It's also more robust than calling RNG 10 times since if you use the same algorithm to seed as for the RNG proper then you will get the same sequences in each instance, just offset.
Point being, the current problematic state of the game is trivially fixable in multiple ways that require half a second's thought (once being aware of the problem).