Relative Strength vs RSI - AB definition clarification, please?

["mroman59" <mroman59@xxxx>]

According to AB help file, RS by definition is: Calculates relative 
strength of currently selected security compared to "tickername" 
security, using SYNTAX relstrength( "tickername", fixup = 1) 

AND 

RSI is a technical indicator developed by Welles Wilder to help 
investors gauge the current strength of a stock's price relative to 
its past performance. It compares a stock's highest highs and lowest 
lows over a period of time. RSI is based upon the difference between 
the average of the closing price on up days vs. the average closing 
price on the down days. 

Problem:

Many investors use a screening method called relative strength to 
filter out stocks that have a value between 0 and 100 which is not 
considered RSI in my opinion. This filtering is the strength of a 
stock price movement over a set period of time which is relative to 
the price movement to all other stocks in the database. The 
comparison to an index is not the objective, only how well the price 
is moving compared to the price movement of other stocks. 

For exmaple: "Filter stocks whose RS is above 85" means screen for 
those stocks whose price movement is in the top 15% of all stocks in 
the database. Again, this is not RSI, because RSI compares a stock 
price to its own past performance and not to that of all stocks. The 
code somehow ranks stocks by percentile (0 to 100) and you 
automatically know which stocks prices are in the top 10% or 15%, 
etc., which ever filter you wish to screen for. The code must include 
the ability to take into account the price within a given period of 
days, for example 1 month, 3 months or 1 year, etc.

At this time I can not find any instructions in AB that would help me 
code and screen for stocks with price movement (or RS) that returns 
all stocks with a selected value (between 0 and 100) which is 
actually a comparison to all other stocks in the database. I have 
used other software applications that performed this function, but 
the code was not available to the user.

Your help is appreciated.
Thank You