You would take up the land purchase by debit the Balance Sheet - Asset - Land account 150,000 and credit the Balance Sheet - Equity - Capital Accounts - Partner 1 100,000, Partner 2 25,000, Partner 3 25,000.
When the land is sold do a Receive Money for 225,000 with the first line Account being Land for 150000
and the second line Account being (P&L) Profit on Sale for 75,000
However, an alternate for (1), if the Partners had paid the funds into a Cash Account first and then purchased the land second would be: Receive Money with separate Account lines for each Partners contribution, then a Spend Money with the Account being Land
You could, but you never expect to buy or sell that land again. Yet the item will remain forever because you once bought and sold it. Unless specific identification is necessary, a generic land account might be more convenient. You could also explore Special Accounts or Custom Control Accounts. Search the forum for discussions about them.