[XeTeX] Kerning in spite of a NWNJ

[Adam Baker]

Although I hope that XeTeX can help me address this question, it might
be more of a Unicode question. I was using XeTeX when I came up with
it. :-)

I just found that when a zero-width non-joiner is placed between two
Arabic letters, kerning rules are not applied. This strikes me as a
bit odd, because in some languages (like Persian) a ZWNJ is used to
force a final form, i.e., to indicate a morpheme break. It's
conceivable that a following glyph would be an isolated form. In that
case, you might need kerning to make the [final]-[isolated] sequence
look better. Is there a way to produce this? (And alternative to ZWNJ
perhaps?)

Thanks,
Adam