Matlab : when if-elseif-else becomes too big (>2000 elseif clauses)

I am having a problem in matlab coding. I have to put more than 2000 elseif in a if-elseif-else condition. Need some expert advice. I searched for it but couldn't find an efficient way. The if-elseif-else is like:

for i-loop
  for j-loop
     for k-loop

      if i,j,k are in (box1 co-ordiate)
             do ..
      elseif  i,j,k are in (box2 co-ordinate)
      elseif  i,j,k are in .................
      ......................................
      after more than 2000
      else 
       they are all ....

     end
end
end
end

your valuable advice would help me a lot. thanks in advance.