Code:Run Macro from Keyboard Shortcut

HELP says: "The shortcut key will override any default Microsoft Excel shortcut keys while the workbook that contains the macro is open."

1. Want to create macro and assign it to Ctl+S in only one Workbook, Workbook A, to save Workbook A in multiple locations.
2. I have Workbooks A, B, C, D and E open at the same time but am working in Workbook A.
3. If I switch to Workbook B, C, D or E (with the original 5 files open) and use Ctl+S, will it save in a normal fashion or will it save to the locations assigned in Workbook A with the new Ctl+S macro.
4. In other words, does the new Ctl+S macro assigned to one file automatically override the Ctl+S default in any other open file?

Thanks so much for your help!