Blackjack can be effectively tackled by groups of players (teams).
There are numerous strategies adopted by teams, and one of the most popular is the BIG player strategy.
Here’s how it works: three or, preferably, more players sit at different tables and count cards, always betting the minimum. They enter the game at different times, making sure not to reveal anything that could link them to each other.
The big player roams from table to table, preferably smoking (if allowed!) and holding a drink in hand. Acting cocky, they place a significant bet at one table or another when, informed through a prearranged signal, the count is high.
When the blackjack count is particularly high, the big player will also place bets behind other players, signaled by the counter. The counter will obviously point out players who have knowledge of basic strategy and/or are easily influenced, to generate even more profit and "fly under the radar."
For this strategy to work perfectly, it’s better if the counters are not always the same but chosen from a rotating pool of team members.
There are other, more advanced and profitable team strategies, but it's not necessary to describe them in detail here.