foo.rb

class Something
  attr_accessor :groups

  def initialize
    @groups = []
  end

  def respond_to_missing?(method_sym, include_private = false)
    @groups.map(&:name).detect { |name| name == method_sym.to_s }
  end

  def method_missing(method_sym, *args, &block)
    @groups.detect { |group| group.name == method_sym.to_s } || super
  end
end

class Group
  attr_accessor :name, :data

  def initialize(name, data)
    @name = name
    @data = data
  end

  def to_h
    { name: name, data: data }
  end
end

s = Something.new
s.groups << Group.new('foobar', 'bazbat')
s.foobar.to_h

s.respond_to? :foobar #=> true
s.respond_to? :bingo  #=> false