This is a serving accuracy drill. The ball is to be served six times by each player. He is to serve the ball once to each of the six players in the two rows. The ball has to reach each player without them having to move from their position. The player is to catch the ball and return it to the server. After the server on each team gets a turn, the team rotates and a new person gets to try.
New hitters rarely miss because of their arm. They miss because of their feet. Build a reliable approach, then time it with your setter.
When your hitter gets stuffed, five teammates standing and watching is how you lose the point. Good attack coverage turns a blocked ball into a second swing.
Coaches spend hours correcting arms in serve receive when the real fault is almost always the feet. Fix the movement and the platform fixes itself.