When you send funds to an integrated address, what you're actually doing is sending funds to the recipient's underlying Monero wallet address and simultaneously attaching an encrypted payment ID to the transaction.
According to the current specification, there can only be one payment ID specified in the tx_extra field. Because of this, only one integrated address can be sent to per transaction.
Unless you can convince the developers of Monero wallets to allow a new tx_extra format that allows multiple encrypted payment IDs to be specified, you're going to have to find a different way of achieving the result you're looking for.
One solution is to "dice up" your outputs ahead of time. If you have one large output of value 100 XMR, then when you spend 1 XMR you'll have to wait for 10 confirmations before your 99 XMR change is available to be spent in a subsequent transaction. But if you do:
transfer your_wallet_address 20 your_wallet_address 20 your_wallet_address 20 your_wallet_address 20
Then you'll end up with 4 outputs for 20 XMR in your wallet and 1 change output of slightly less than 20 XMR in your wallet (because of the transaction fee).
Therefore you'll be able to send several transactions in a row, each to a different integrated address, and you won't have to wait because you'll be spending from your unlocked balance in future transactions instead of from your locked change balance.