Sandhi phones

My LLL language Mærik has [T] and [x], but only under some
very well defined conditions.  The first is fairly simple:
they appear as allophones of /D/ and /G/ next to voiceless
sounds, but when that voiceless sound is homorganic with
the fricative there appears a "free-standing" [T] or [x].
In a very superficial phonemic analysis they would count
as phonemes, but in effect they represent underlying
/tD/ and /kG/(*) -- always across a morpheme boundary,
so my hunch is that they are not really phonemes in their
own right.  So now i have two questions:

1) Does anyone know of an ANADEWism for this?
2) What are such sounds that straddle between
phonemes and allophones called?  I tentatively
call them "sandhi phones".

(*) Strangely /Dt/ and /Gk/ seem to become [tt]
and [kk], presumably because this assimilation
was earlier.  FYI -dh and -gh are the accusative
and instrumental ending, syncopated from -adh
and -agh.
--

/BP 8^)>
--
Benct Philip Jonsson -- melroch at melroch dot se

         Solitudinem faciunt pacem appellant!
                                             (Tacitus)