ruleset template display table display the selected value of the 0 to more type value hold from rule template

Hi,

I have a ruleset template (RST), it has a value Holder RST_VH1 (type: RT1 refer to the rule template, count: 0 to more). In the RST display format it is a display table for displaying the rules as table format.

In my rule template (RT1) it have value holder  RT1_VHA( count: 0-more, type: templateA), value holder RT1_VHB (count: exactly 1), value holder RT1_VHC (count: exactly 1). 

The templatA has a value holder TA_VHA it display as choice box, count: exactly 1. (choice box options values are: AA, BB, CC, DD, EE,..)

In the RT1 screen user define the rule they can input the value for RT1_VHB, RT1_VHC . they can also add more than one RT1_VHA, each add they choose a different value from the choice box.

Currently my RST display table contains 2 columns, they display the value of RT1.RT1_VHB, RT1.RT1_VHC of each rule.

Now I want to add RT1_VHA as another column to my RST's display table. This new column will display the string concatenation of user's choice of the RT1_VHA values.

That say for rule1 user add  AA and DD as RT1_VHA; for rule2 user add BB, CC and EE as RT1_VHA; for rule3 user didn't choose anything as the RT1_VHA. Then I want the new column shows  "AA,DD" for rule1; "BB,CC,EE" for rule2; "" empaty value for rule3.

Please suggest is this doable and how to do it.