Isn't this something similar to bullying? Why not putting dust on the floor to make them slip away or hit them as a partner """""accidentally""""" to make them injured and stay home for a few weeks?


IMO the best way to make them lose the interest to play better opponents is to play serious. This has also the advantage that you spend less time with them on court -> shorter rallies, less rallies -> shorter game. They may get frustrated and would leave or refuse to play in the future. It can also motivate them to become better to fit in. I really hate if somebody don't take his/her opponent serious, toy around and make them look like fools. This is some kind of disrespect and not great sportmanship if you do this cat and mouse game.
At the end of the day you need to ask yourself if you are at the right place if you want to get rid of certain players. Everybody claims to have good and challenging games, but we should also give it to others to let them improve, especially in a supportive enviroment of a club. If you want to spend time just with selected players a private booking court might be a better idea.