Hi,
You can use the Script unit http://www.webratio.com/learn/article/Getting-started-with-the-Script-unit, it is no difficult, in a script unit you can use groovy and java lenguaje, for example,
#input Integer a, Integer b //a and b are the input variables
#output r // r is the result
Integer res=a*b //for example the res is equals to a * b
return ["r":res] // return the variable with the result
You can create a loop in the scritp with groovy
for (i in list) { ....}
or java
for (i = 0; i < 5; i++) { ... }
you can have the input arrays and you can do a loop and create a string concatenate with your data as you develop in java and as return you can have a variable with all concatenate string for example:
"<table><tr><td>name1<td></tr><tr><td>name2<td></tr><tr><td>....<td></tr></table>"
I hope to help