Jamba is an addon that helps you multibox with a lot of features such as alerts as you said, quests ect... but it's not enough to multibox, as Repc said, you gonna need a 3rd party software.
I highly recommand you to use ISBoxer, which is absolutely the most complete Multiboxing software, it's not user-friendly but there are tutorials on YouTube (check Multiboxology channel, he made beginner-setup tutorials and pro-setup tutorials).
The software cost 50$ per year (I wouldn't be a problem I think), you can always use the cracked version but it has a keylogger in it so...