Mutable pronouns in Lyrics

[Br. Samuel Springuel]

I have some hymns which are sung on the occasion of saint's days which 
have pronouns which refers to the saint.  Obviously, these pronouns 
should be either "he", "his", "him" or "she", "her" depending on the 
gender of the saint.  When producing scores which are unattached to a 
specific liturgy, I would put "he/she", "his/her", "him/her" in the 
lyrics, however, when including the hymn in a specific liturgy, I would 
like the pronoun to take the appropriate form.  Is there a way to write 
(scheme) functions that allows me to set a flag at the beginning of the 
score indicating which pronoun type I want and the lyrics will change 
accordingly.

MWE:

\version "2.18.2"

gender = m % manually set to m(ale), f(emale), n(eutral)

heshe = he % change to function which picks between "he" "she" and 
"he/she" based on setting of \gender

hisher = his % change to function which picks between "his" "her" and 
"his/her" based on setting of \gender

himher = him % change to function which picks between "him" "her" and 
"him/her" based on setting of \gender

global = { \key c \major }

verse = \lyricmode {
  Filled with the Spir -- it, by \hisher earth -- ly la -- bours,
  Brought to your peo -- ple heal -- ing and com -- pas -- sion;
  Rais -- ing the fal -- len, re -- con -- cil -- ing sin -- ners,
  Glad -- ly \heshe served them.
}

music = {
  c' c' c' c' c' c' c' c' c' c' c'
  c' c' c' c' c' c' c' c' c' c' c'
  c' c' c' c' c' c' c' c' c' c' c'
  c' c' c' c' c'
}

\new Staff
<<
   \new Voice = "mel" { \global \music }
   \new Lyrics \lyricsto "mel" { \verse }
>>

--
✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝
Br. Samuel, OSB
St. Anselm’s Abbey
Washington, DC
(R. Padraic Springuel)

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