def split_list(seq, m='@'):
 r = []
 t = []
 for i in seq:
  if t and i.startswith(m):
   r.append(t)
   t = []
  t.append(i)
  if t:
   r.append(t)
 return r

print split_list(['foo', 'hoge', '@fuga', 'piyo', 'moe', '@hoe'])