Which is which

So what I want to know is the equivalents of the R9 series cards. Like what are the equivalents, to the 270x, 280x, and 290x, in the 7000 series

270x = 7870 (Pitcairn) and is crossfire compatible with one another

280x = 7970 (Tahiti) and is crossfire compatible with one another

290x = (Hawaii) no equivalent, is new king