My configuration for 4 boxing sorcerers
Alt F Set Focus Target
Ctrl F Acquire Focus Target's Target
[ Follow Target
There are other mappings but they are mostly the standard game mappings. A key part of this to work correctly are the Variable Keystrokes assigned to each of the slots in the SWTORXplorer character set. These work because each time the group is formed with invites, the group always stays in the same position for the function keys to select a character in the group. If your group is formed in a different order, you may need to change the Variable Keystroke for the correct slots to be targeted. I think it can change depending on your group order, but once set, your group is always formed in the same order unless you change their name or use a different character. I got the Variable Keystrokes from someone else on the Internet, don't remember where, but I had to change one of them because one of my characters would not select the right character to set focus for. Another key part of this is Alt 9 which sets focus. In game, Alt F sets focus, but my ISBoxer config has Alt 9 to target the appropriate slot that is active at the moment and then send Alt F to set focus. This must be done every time a zone change occurs such as entering an instance. If that is not set, the characters won't assist properly. I couldn't find any other way to do assist without setting focus and followed many other videos but they appear to be old prior to follow being fixed in the game. So after Alt 9 sets focus, the 9 and 4 keys are used to target the same enemy that the active window has targeted. This allows all characters to target and attack the same target as the active window.
I couldn't find a way to acquire focus target and follow in the same keystroke. No matter what I used it would stop before completing. I originally used the Manifesto posted on youtube at http://www.youtube.com/watch?v=qeFRR7NeMds but that is very strange in that the characters keep on jumping around when they follow each other. With my method, the characters just follow with [ and assist/attack with 9 or 4.
The keymap SWTOR Control allows turning off the mapping with Alt Pause and turning it back on with the Ins key.