Group Transfer from CDG to Le Pocq

If you mean St Germain en Laye, I would take a taxi from the official taxi queue. Do not accept offers from clandestine drivers soliciting from within the terminals. You´ll pay the metered fare plus 4€ additional for each passenger after the 4th.

Taxi drivers are not tipped.

You may need 2 taxis, since 6 people with luggage would likely be too much for just 1.

Have you asked Viking?

Paris (Le Pecq), France

Arrive in Paris, romance capital of the world. Transfer from the airport in Paris to your ship.* After boarding, take free time to explore Paris, or join our “welcome walk” to stretch your legs and get oriented. (D)

Note: The Paris port authority assigned Viking a docking location in Le Pecq, a western suburb of Paris. To help maximize your time in the city center, we are offering complimentary shuttles for Viking guests throughout your stay.
* Ground transfers are included with Viking Air purchase.

The above is from the Viking website. It is unclear to me who get the free shuttles, but it would not hurt to ask

Taxis from CDG can carry up to 7 passengers and luggage. There is an additional fee for passengers after 4 but you will not need two taxis. Just let the attendant know how many people are in your party, and he´ll match you with the appropriate vehicle.