I’ve run into something similar with condo associations. In QuickBooks, by default, equity is lumped into Owner’s Equity, which isn’t very helpful for tracking separate funds.
What I usually do is create a separate equity account for each fund under your Chart of Accounts, like Fund A Equity, Fund B Equity, etc. Then, when you set up your opening balances or record any fund-specific surplus/deficit at the end of the year, make sure the adjustment entries hit the corresponding fund’s equity account, not the main Owner’s Equity.
Basically, every time income comes in or you close out a period, you move the net to the correct fund equity account. That way, your P\&L stays clean, and the balance sheet shows each fund’s actual equity instead of everything rolled together.
I also like to use classes or locations per fund, then you can run reports that split the numbers without manually tracking everything. It’s a bit of setup upfront, but once it’s in place, it keeps your funds accurate and transparent.