You don't need to re-sync the whole ethereum chain. You can use the chain you have stored in your disk, and use geth from the command prompt typing:
.>geth export ~\file.bin 0 1919500
If you use the last geth version it takes just 4 or 5 minutes. With the older geth versions, may take longer.
This will save in your disk, the ethereum blockchain from the genesys block to some block near but prior to the HF (like e.g. 1919500).

Then you can import this bin file to each data directory with the command:
.>geth import ~\file.bin
This will take way longer, but nothing to say to re-sync to the whole blockchain.

After that, you'll be syncing just the last blocks of the chain (main or classic)