No.
Your pump may be rated to 3000 psi, so any hyd component can try and develop the pressure and therefore power.
You can work two cyl at the same time and they both can develop up to the 3000 psi rated pressure, depending on the relief valve setting.
All the valves in an open center hyd system are in series, so all valves will see the pump flow.
The first valve can take all the flow leaving none for the other valves.
If you only use half of the flow, then another valve can use the remaining flow, and still develop the 3000 psi.