help create two-symbol Indicator

[venture99]

Goal is to use two symbols with one indicator (like STOC or CCI) for each, then create the subtraction ( spread) of one indicator from the other, ie, the difference would be a new indicator. How can this be done?
Maybe some math whiz can prove that it is the same thing to create a difference (spread) between the two symbols first, then use a plain indicator on the difference. Does anyone know if this might be true? and under what conditions?
Regards, Will

[venture99]

Can some efs expert please take a look at this question?
It represents a powerful way to trade spreads, if it can be implimented in eSig. If not, guidance would be appreciated.
Regards