how can I run multi wallet on one computer to share same blockdata
On Windows it wouldn't work because of file locking/sharing I suspect and on Linux that wouldn't be a problem but the data would surely get corrupted. There's no advantage to running multiple servers either, if you need to process more transactions than the server can handle then you should probably be doing it a different way or with multiple machines. If it's to help the network then one will do - leave it 24/7 and it will start to provide more than 8 connections if you allow it via config.