As I understand a stale share is a share which was sent to the pool by another miner before yours sent it. So your miner sent a share which already was accepted by the pool. When you know this you understand why only the pool knows which share is stale is and which isn't.
When two miners send same share it's called a duplicate share.
Stale share is a share that is sent too late, when pool is already working on new block.
Don't you want to add a new option into your miner: to set epools.txt (dpools.txt) files as options in command line or in config.txt file. That will let user to launch just different bat-files when switching to another coin without making each time changes in epools(dpools)-files for new alternative pools.
Ok, I will add it in next update.