Macros for specific programs

Using Windows XP, is it possible to write macros that work with one program only?

I have a program that requires use of the "Home" and "End" keys constantly. On my little EeePC laptop, these are shared keys:

Home = Function + Left Arrow
End = Function + Right Arrow

Unfortunately, there's only one Function key and I can't reach it with one hand.

I'd like to have a macro that uses the Ctrl, or Shift, or Alt, or Tab keys to toggle between "Home" and "End" with just one keystroke. These keys aren't used for anything else in the program.

Can it be done?