Reporting positive and negative customer balances separately.

[Buddha Buck]

I'm treasurer for a membership organization, where our main income is
monthly membership dues.  Some of our members pay their dues well in
advance, some are delinquent in paying their dues.  I suspect this is
typical of many organizations/businesses with recurring monthly
payments/subscriptions.

Currently I am using accrual bookkeeping, and using the business tools in
GnuCash to handle this.  When a member joins, I create monthly invoices so
that the income from their membership is spread out across the year, and I
record their payments when they make them.  This means that for some of our
members they show a net credit when I look at their Customer Report, and
for others they show a net debit.

On the Balance Sheet report, and on the Accounts tab, the balance shown for
A/R is the total dues in arrears less the total dues paid ahead.  If Tom
hasn't paid $50/mo for 3 months, and John is ahead in his dues by 3 months,
the balance sheet will show and A/R balance of $0.

This is all expected, and reasonable, given how this is all supposed to
work.

However, I have been asked by the other officers in the organisation to
report on the amounts paid ahead, and on the amounts in arrears separately.
 They are concerned about getting overconfident by a large cash balance and
spending money now that we will need in the future.

Right now, the only way I know to do that is to generate a Customer Report
for all the members individually and manually sum up the balances.

Is there a way to customize the balance sheet report so it'll split out A/R
into the two types of account balances?