Income division in fund based accounting

[David G. Pickett]

A major complication in fund accounting for non-profits is the division 
of income.  The various funds in a category can share in a bank account 
or investment vehicle like a mutual fund or account holding multiple 
mutual funds.  Depending on the nature of the fund and associated 
policy, the income may be diverted to administrative costs (gotta pay 
the overhead of having the money managed), but in some cases that is not 
appropriate or desirable, or even legal.  The income, loss or change in 
cash value of the account needs to be divided between the funds 
participating in the account pro-rata, and the accounting software needs 
to adjust ownership proportions every time a fund makes a transaction on 
the funds.

For instance, suppose Fund A is established with $10,000 and Fund B with 
$20,000, and the money is put in a Vanguard account in a mutual fund:

 1. Fund A owns 1/3 or 33.3333% of value at Vanguard.
 2. When a dividend of say $387.29 is received, either as cash in the
    trading account or reinvested, now Fund A has $10,129.10 at
    Vanguard, still 1/3 or 33.3333%.
 3. If the underlying funds rise in value by 11%, now it has $11,243.30
    at Vanguard, still 1/3 or 33.3333%.
 4. If Fund A transfers $2,000.00 to a bank account for distribution ash
    checks, now it has $9,243.30 at Vanguard, or 27.4039%.

The desire is to have software that juggles the ownership gracefully, 
precisely, without excess transactions and with accurate reporting.  If 
all the fund values add up to more than the account value due to 
rounding up, what do you do (even with biased rounding, there might be 
ties for amount or age of value owned by each fund, so this might have 
to a bit random, like last guy loses a penny, as with going down the 
owner list alphanumerically and pulling their value from the whole, and 
dividing the remainder among the rest, recursively)?  Fund accounting is 
almost like running a bank!  Banks have to round loan interest down, so 
they do not charge over their promised rate, but they do not seem to be 
so constrained with savings interest.

Can GNUCash deal with this somehow?