Lightroom file export without changing dpi

Is there a way to export the file as is no dpi changes. Or some plugin to help woth this seemingly simple problem?

Example:

5 images all edited to different sizes, eg 8x10 12x16 etc at various dpi for print.

When i export the dpi setting is fixed and messes up all the files. Now they are all one dpi and no longer theri respective sizes.