How to write 5 day RSI of 3 day rateofchange formula???

[dburkey@xxxxxxxxxxxxxxxx]

Please help: 

I'm trying to write a formula that will show me the RSI of something
else other than close. 

RSI(10) shows the basic 10 day rsi. 

Example of what I'm trying to do:

5 day RSI of a 3 day rate of change. 


Omega Supercharts lets the user simply use RSI(rateofchange(c,3), 5).

Is there a similar formula in Metastock?? 

Thanks, 

Dennis Burkey