Can multiple wallets send 1 transaction for the combined balance? I have multiple wallets, I want to transfer all of the money to 1 wallet of some other person. But I want to do this as one transaction to avoid fees. Is this possible with bitcoind API?
If you are using a wallet which supports importing private keys, such an Bitcoin Core, you can just import the private key of your other wallet: https://bitcoin.stackexchange.com/a/5944/14325