[Feature request] Fine tuning config for historical sync

Hello,

Since 1.5 landed on the testnet I've managed to reset my backup historical node to test the new historical sync.
It's working fine overall for now however, to speed up the process, I'd like to have fine control over which nodes it connects to for the historical sync.

In my case, I run multiple nodes : 2 mainnet, 3 testnet - 1 one main, one backup historical, and one non-historical.

Given that my node(s) have high-end hardware, it would make sense to make them discuss only between them to sync and change the parameters of the config file to allow more traffic/discussion between them.

Overall, there's always the option to make a backup of a fully synced node and load it on another server, but in the case of exceptional data loss, a month or more to sync historical data is a little bit long. And in a cloud-native environment, it would make more sense to delete a bad node (data loss, database corruption, or anything else) and spin up a new one that will sync from a specified array of nodes.

In the actual config file, we have parameters to protect the node itself, but no parameters to modify the sync speed or anything like that.