Gloss field, MDF and ISO639-3 language codes

[Ian Scales]

I'd like to get feedback from anyone as to whether the following is a
good idea, and how it might be implemented technically by the Toolbox
development team.

At the moment I am working on my second serious dictionary project in
Solomon Islands. Ideally this dictionary should cross-reference
glosses to a number of nearby languages. That is, if I happen to know
that the word for "axe" three languages away is nearly the same, I
want the dictionary to note that.

In my first dictionary project, I simply used the \gr and \gn fields
to gloss to a couple nearby languages. These would show up in the MDF
output, and I'd search-and-replace in Word to change "Regional:" to
"Roviana:" and so on. But I want more.

I want to be able to use the ISO639-3 language codes as gloss fields,
so: \gbgt (Bughotu, bgt), \gnlg (Gela, nlg), etc. Fiddling around with
cc tables to bodge this up myself is not at all my cup of tea.

Toolbox/MDF should be able to handle the ISO codes in native mode.
Type in "\gbgt pela" and the MDF output should already know to end the
entry with "Bughotu: pela."

Does this seem a good idea to others? And if so, then how might this
be done by Toolbox? I imagine a new cc table as part of Toolbox with
all the ISO codes inside. This would interact with the marker list
range set (you'd still have to accept the markers you actually want in
the project's range set, because otherwise the range set would be
totally cluttered). Or what?