To be clear, you have receive a gift (or more likely are the beneficiary of an annuity) payable over multiple years.
In your GL, you would credit 'Income - Restricted gifts' or whatever equivalent account you have and debit cash (for any amount received in the current year, short term receivables (for the amount to be received next year), and long term receivables for the remainder. At year end, the Income - Restricted would be closed out to your Restricted Gifts equity account. Also, any expenses which meet the purpose of the gift are closed to that account.
In practicality, however, most organizations post the NPV to Accounts Receivable.
So, a thousand dollar gift over five years with an NPV of $920. (i am just splitting the interest for this illustration)
Debit Credit
AR 920
Restrict Income 920
1st year pymt
Cash 200
AR 200
2nd year
Cash 200
AR 180
Interest inc 20
You may commingle your funds, but as you should not 'borrow' from restricted gifts, you must ensure that your investment fund never goes below that amount of restricted gifts actually received and not used for the restricted purpose.
In the example above, assume there was a $100 expense that met the requirements of the gift in the first year and none in the second year.
At the end of the first year, your investment fund could not drop below $100. After the second gift was received, it could not go below $200 until more qualifying expenses were met.
Because of the possible complexity, most organizations do have a separate bank/investment fund for Restricted gifts. some even have a different account for each restricted gift.
Kirby Bowser