Unfortunately I don't think it's currently possible to to track
it other than an aggregated portfolio. It's not possible to do
split transactions in the register of an Investment account, so
unfortunately that rules out that option.
I'm going to consult with the rest of our staff regarding this
to see if someone has a better solution than this, but I do think
that there's probably not a better way.
Since the inherent nature of a 529 plan is that of a long term
investment and you have no control over the allocation of the
aggregated fund, personally I would treat it as singular
For performance tracking purposes, I would probably enter a
weekly NAV manually. There is a free extension offered by Songline
Software that may make the price entry process a little more