I want to find at least two (better more of course) private keys within the bitcoin range and leading to the same btc address.
What you are looking for is either one of the following to have occurred:
- A SHA256 collision (2 different inputs that result in the exact same SHA256 outputs)
- A RIPEMD160 collision (2 different inputs that result in the exact same RIPEMD160 outputs)
To my knowledge, there is no record of either having ever occurred (in Bitcoin or otherwise).