Message determination

HI

Please give me the tips on following question.

In message condition records , MN04 ---enter output type (ZNE) , we are creating condition for different combination like document type / Porg / Vendor. thenenter we will get the input fileds .. medium , vendor etc...

Here i need to create our own combination key like PORG / VENDOR / PLANT/ Purcahse order etc..

Thanks in advance..