How to draw trendline object to indicator window?

Hi Everyone,

I would like to draw 2 different trendlines to the chart.

First goes to Main Chart.

And the second goes to indicator window but I do not know how.

Here is an example (RSI divergence):

Red trendline made by Sample indicator by the following code:

Chart.DrawTrendLine("TrendLine1",time1, price1, time2, price2,Color.Red);

But I do not know how to draw the pink trendline to indicator window.

Thank You