Linn LK240 bi-amping confusion

I just got a bunch of Linn gear at auction. I want to actively bi-amp or tri-amp my Ninkas with either Lk240s or possibly Lk280s. I believe the LK 240s are mono. Do I need 6 of them to tri-amp two speakers?(!)
I don't see any place to attach an Aktiv crossover board to the lk240 board, or any hole for a adjustment pit to stick out the rear. I do notice that in small writing on my board, one area says "AKTIV CROSSOVER" (see photo)
Is it possible that theaktiv crossover is built in?

Also, on the rear are two RCA plugs labeled "audio input" Is input the same as output in this case?
There are 4 speaker out puts labeled 1-4. Are they the same? Thanks in advance for any help!
Charley
PS If anyone wants to take all this off my hands let me know!