Question

Go to:

https://www.sythe.org/conversations/add

You input names by typing them out separated by a comma in the top box to invite multiple people.

So to add multiple people you would write:

User1,user2,user3,

as an example. This is not case sensitive.

You can also navigate to the above link yourself by clicking on inbox in the top right of the site and then clicking start a new conversation. Peoples' profiles will also have a button to start a conversation (provided they are not banned/don't have a Do Not Trade rank.)