How would u balance the charges in your suggested system?
If the hydrogen ions are dishcarged and the inert electrode remains unchanged throughout the process, then there will be a build-up of residual negative charges (from the acid derived anion) and build-up of positive charges in the block of more reactive metal.
You may immerse the more reactive metal block into the solution, together with the connecting wire. In this way, the less reactive metal block will still be chemically shielded from the acid solution at the same, faciliatata the flow of charges.
You may try cathodic protection. By imposing a small current flow into the metal block, the chemical potential of the metal block is changed such that it is less reactive consequently. By adjusting the current flow, the metal block can be made to be inert to the acidic agent.