multisplit=: 4 :0
  'sep begin'=. |: t=. y /:~&.:(|."1)@;@(i.@#@[ ,.L:0"0 I.@E.L:0) x
  end=. begin + sep { #@>y
  last=. next=. 0
  r=. 2 0$0
  while. next<#begin do.
    r=. r,.(last}.x{.~next{begin);next{t
    last=. next{end
    next=. 1 i.~(begin>next{begin)*.begin>:last
  end.
  r=. r,.'';~last}.x
)