You can't create a single array that has multiple scopes. The scope of an array depends on where and how it is defined.
Not sure what you're trying to accomplish. Since you seem to have an Account class, you may want to incorporate the concept of a scope as an attribute in your class.
What I mean by that is consider how a symbol table works. Symbol tables might be implemented as a std::stack<std::map>. When the compiler starts, it pushes the map for the global scope. When a function is encountered, it pushes another map on the stack that will contain the local variables.