How does one go about plotting several equities on one chart and having all of the equities start at the same value.

If I look at an equity in Morningstar.coms web site and then add other stocks to compare the base against it starts them all at the same place. It appears to do this by taking an equivelent cash amount and trending that. $10,00.00 in each equity as a starting point and then running the trend forward to the current time.

Do I need to do the same thing by developing a composite security of each and then plotting those composite securities or is there some way to do it automatically?

Example: Equity A = 1.4Equity B