BTC Transfer from One Exchange Vendor to Other Exchange Vendor
I've marked this as a duplicate of a 'my transaction isn't confirming' question, there is a lot of good info if you look at the answers there.

One additional note: when sending from one exchange to another, you do not decide the fee. The exchange controls the keys that spend the coins, so they will set the fee for you. If you control the keys of your coins yourself, then you can choose the fees when you spend your bitcoins. 

Exchanges can choose to 'batch withdrawals', which means they will send multiple withdrawals to customers as a single transaction with multiple outputs. Batching a transaction allows the sender to pay less fees than if each transaction was sent individually.