If I paid $20 to fine-tune a model to do X, and you paid $20 to fine-tune a model to do Y, is there a way to merge models, aggregating X and Y training, without

If I paid $20 to fine-tune a model to do X, and you paid $20 to fine-tune a model to do Y, is there a way to merge models, aggregating X and Y training, without training from scratch again?