5 adults to Peninsula hotel from Beijing Airport.

Usually, a taxi is able to take 4 people, thus you need 2 taxis. Since you are 5 adults, I suggest you take the express train to Dongzhimen and transfer to subway line 2 to Yonghegong lama Temple. Then take subway line 5 to Dengshikou. Get out of the subway station from exit C and walk about several minutes to your hotel. It may cost about CNY30/person. Or you can take the airport shuttle bus line 3 to Chaoyangmen and then take taxis to the hotel.