Corel DESIGNER 12 already provides even more than that:
The Symbol Manager (Ctrl+F2) provides a view to libraries with ~4000 symbols (including electrical symbols for various types of plans and diagrams).
With drag&drop you can use any of these symbols in your illustrations. You can create your own symbols just by right click on the graphic object / group in the drawing and then create a new symbol from there.
Symbol libraries can be created by saving a file with all symbols as *.csl (Corel Symbol Library). Saving to a network drive and making the folder with that libraries available in the Symbol Manager (there's the "Add Library" feature in the Symbol Manager docker) gives the option to link such symbols as external reference to a Corel DESIGNER file.
Whenever you have to update a default symbol you can do that from the central library and then update all entities in the files using this symbol with one click in the "Link Manager" (in the Window menu).
The same update option for symbols you have within a file (with symbols that are defined within the *.des file).
Have fun with exploring this feature!