Recently the Multi-Peer-Multi-Asset (MPMA) feature has been added to Counterparty which allows users to send many assets to many addresses in a single transactions, unfortunately due to counterwallet being outdated and difficult to maintain, the MPMA feature was not integrated into Counterwallet, so while the new feature works great, there is currently not any way to send MPMA transactions.
I have been working on getting MPMA support integrated into freewallet desktop and expect to put out a new release soon with support for this feature.
In the interim, I have written up this handy MPMA send tool which takes a private key and a list of addresses, assets, and quantities, and handles generating an MPMA send transaction.
The source code for this tool is available at the link below (so you can verify that none of the code is trying to steal your private keys, etc)
Here is a transaction which was just sent using this tool