Feat that adds skill points

[Greylin]

Hi all, I am trying to code the below feat for our new pirate-themed campaign (Arrr....!)

--snip--
A Life At Sea: You receive a +2 bonus to any two of the following skills: Craft (sails), Craft (ships), Knowledge (nature), Profession (navigator), or Profession (sailor). If you have 10 or more ranks in one of these skills, the bonus increases to +3 for that skill.
--snip--

As a quick and dirty, I think I can figure out how to add +4 skill points which the player can allocate as they like - that will at least get us to something that is good enough for the first session.

But I have no idea how to even go into a feat that adds extra points to one of a number of skills. Unless I coded different variants of the feat for different skill combinations, though that seems a clunky workaround.

Any suggestions?