OOS Equity Curve

Does anyone know if/how you can save the Out of Sample Equity Curve in a walkforward optimization? Yes, I know how to save the typical normal backtest equity curve (~~~Equity); I'm talking specifically about the OOS equity curve (~~~OSEQUITY). I see that there has been some discussion on this in previous posts, but nothing specific enough to implement. I've tried to merge the ~~~OSEQUITY to a blank symbol, but that didn't seem to work. This should be very important to anyone who trades more than one strategy. Any solution to this would be very helpful. Thank you in advance.