Sure they were all chained to Zhaitan, some champions can command low ranks, but not all the Risen share the same knowledge. It’s not a hive mind structure like the Destroyers.
In Seas of Sorrow
Cobiah submit himself to the Indomitable’s crew, Sethus even talked to him for a little while.
[b] Captain Whiting turned his greenflame eyes away from Lion’s Arch, cursing in a language that had died long before he was born. “Continue firing on the large galleon…what is this?" The Captain turned to stare at Cobiah. “What have you brought me, lads?”…
“It’s the deserter, sir.” Tosh dragged Cobiah forward. [/b]
But Captain Whiting still didn’t know what did his crew bring him at first. He had to ask about it. He also had to speak to give his crew order rather than simply let his thoughts go through his men’s mind. They are even on the same ship and don’t share a common mind or have the same knowledge.
Also in the Whispers’ Plan of the Pact story. It’s even more clear that the Risen don’t share the same mind and knowledge.
The Pact firstly cleared the Risen in the lighthouse, misdirected the light to lure the Dead Ships to a location. If the Risen share the same mind, they would have realized that the lighthouse was occupied and there were something wrong with the light. But they didn’t, three ships were caught in the trap.
Then we cleared a few Dead Ships, if the Risen’s minds were all connected, they would have known our plan and realize that these ships were used by the Pact. But it didn’t happen until the Eye of Zhaitan had seen our action.
So it’s obvious. Sure they might have some links, especially the champions could command the troops, but not all Risen’s mind are not connected or share the same knowledge.