Did you have a prolonged dry spell followed by a period of heavy rain? This condition would cause peaches to split. Once the process has started I know of no way to reverse or minimize splitting.Perhaps others do.

There is no way of reversing the process once they start to split. You can still use the fruit, just cut out the split in the peach, but this is usually done with peaches that are almost ripe when they start to split. If they start to split in the early stages then mould will get in and cause them to rot on the tree.