Adding new fingering system

[address@hidden]

My main instrument is the Pedal Steel Guitar. One of the different 
things about this instrument is that it has pedals that re-tune specific 
strings.

I want to be able to add strings to my score.

This is close to the result I want, but it would be nice to use a 
similar syntax as for string indications, e.g.
{

\set stringNumberOrientations = #'(up)

<c'\8>4

<c'\8 e'\6 g'\5>4

}



%% Start of file
\version "2.14.2"

{

c'4 ^\markup {\circle \tiny "8"}

<c' e' g' >^\markup { \tiny \left-column {\circle{"5"} \circle{"6"} 
\circle{"8"}}}

<f' a' c'> ^\markup {\tiny \left-column{\circle{"5B"} \circle{"6A"} 
\circle{"8"}}}

}

%% End of file

NB! Here I have added an F chord which uses two pedals (Pedal A and B)

How hard is it to extend Lilypond so I can use the same syntax as for 
string indication?
And where to I start?

// Anders