You can migrate your wallet to Bitcoin Core and use the function called sendmany.
I was reading up on sendmany. Does it have to be done from Bitcoin Core, or could it be done from a GUI type wallet, and if so, where is it!?
Also, I'm not clear on the fee savings of using sendmany. You're sending more bytes because you have multiple addresses, so how does one estimate the cost/savings of actually using the sendmany function vs sending each one separately?