There is widely used multiassist macro.
Like it:
/macro assist /assist Oshitcaller \n /assist backupcaller \n /assist maincaller
If I post it in chat with "." before it - it's ok, and you can copy it and make your macro

But if I make it in blob - it shows ok, but if you click - all after 1st \n is cut out.
<a href='chatcmd:///macro assist /assist Oshitcaller \n /assist backupcaller \n /assist maincaller'>assist</a>
This is my link.

Is FC problem here, you cant make multiple assist on a link it looks like ;[ tryd alot that lol