Depedent Code list in Activity task??

Hi Experts,

In Activity task We have a code list for Category i.e ActivityGroupCode. and i have two more configurable code lists in which i have more number of drop down values in each custom drop down field.

lets assume those two custom code list fields as Codelist1 and Codelist2.

My requirement is based on the category selected by the user i have to filter the codelist drop down values showing the Codelist1.

To achieve this i tried to add the category field as an attribute in the Codelist1 BCO and tried to activate it. But while activating with the standard category field as an attribute in the BCO of the custom field Codelist1 its throwing an standard error .

I raised this to SAP , I got the reply as it does't work with the standard category field as an attribute in the other BCO.

Now i changed the approach as Instead of using standard category field i have created a custom code list field as ZCategory .

Now all the three codelists are custom only.

below is the BCO .

Now i tried using this custom Zcategory field as an attribute in the Codelist1 BCO and activated that BCO . Its activated succesfully.

While adding the dropdown values in the BC Set of the Codelist1 , I have given the same key for the Codelist1 field with diffrent attribute values ,

Why i have given the same key for this field is, based on this field values also i have to filter the codelist2 drop down values..!!

I.e based on codelist1 value i have to filter codelist2 values and based on codelist 2 value i have to filter codelist3 dropdown values.

But here its throwing the error message as key should be unique, In this case it should take both key and attribute value into consideration right??

please check the below screen shot for the info.

In the below screen shot , I have given contact reason(alias codelist1 ) key value same for two entries and category attribute as different that is request and complain, Ideally will this work or this is wrong approach.

If you have any idea how to do this , Please suggest me a different approach as well.

i read all the scn links which are there in the cloud studio space..!!!

I can write the ruby script for this requirement , If it would have less number of drop down entries , but i have more drop down values in the codelist 1 and codelist2.

Thanks for the help,

Mani