I don't quite understand what you want, but XVI32 has a Search, Replace, Count, and Replace All. You can do all of these either from the beginning of the file, or from wherever you place the cursor. And you can do them forwards (from wherever you start to the end of the file) or backwards (from wherever you start to the beginning of the file).
I really want a hex editor that allows you to Count and Replace All between (x) offset and (y) offset.
I think either HxD or Neo allows you to Search, Count, and Replace All over multiple files chosen, or all the files in a specified directory. That's really useful sometimes.
Most of the non-crappy hex editors have scripting features, which should allow you to create what you need it to do.