Currently, that kind of feature doesn't exist.

Sounds like a nice idea but I bet it's not going to be simple task for this one, need to consider the text length, make sure it's takes in all language characters + the SET is actually an image and not a font I think, so they would need to replace that part with text with similar font. Etc...

Might be possible to have an alias show up on chatlog or something but dunno if that's going to be good for anyone. /alias SET1 "Single Target" > when you switch to SET1 it displayed XHB switched to "Single Target" in chat log.