It isn't exactly what you're looking for, but you may find this interesting, and it's a bit of an insight into the relationship between pretraining and fine tuning: https://arxiv.org/pdf/2503.10965
That basically just sounds like Mixture of Experts
It isn't exactly what you're looking for, but you may find this interesting, and it's a bit of an insight into the relationship between pretraining and fine tuning: https://arxiv.org/pdf/2503.10965