Just a tip about this: you can view all the commands in-game. Just open up your macro editor (User Macros) and click on the button Text Commands on the bottom right of the window. If you select any text command you'll get a brief explanation about usage (which you can also have displayed on the chat log using /? [text command], i.e. /? /psort).
Furthermore, you can create a macro for welcoming new party members and sort them out on the party list:

/psort
/p {Hello!}
/welcome

Once done, you just drag & drop the macro to your hotbars and click it whenever you need to.