Given a sorted array of numbers will group the numbers so long as they are within a given delta of each other. That is to say will group numbers that are close but once a gap is found a new group is started.

group.rb

times = [1,2,4,5,10,12,14,20,22,23,24]
@group = 0
@delta = 3

def group(times)
  times.group_by do |item|
    index = times.index(item)

    if index <= times.size - 2
      a = index + 1
      b = index
    else
      a = index
      b = index - 1
    end

    if times[a] - times[b] < @delta
      @group
    else
      @group = @group + 1
      @group - 1
    end
  end
end

puts group times