how to enable workflow for a vaersions wise ?

Hi ,

I have customized a sales order workflow . In that i have configured workflow .in that two versions are there

i) for first version( i have created 4 sale orders

2)for second version( i have created 5 sales orders

Now irrespective of versions workflow is enabling ,…but i want to enable the workflow based on version .

Ex: I have activated workflow for version , so need to enable workflow those 4 sale orders only not all sale orders

If any one knows please help me out

Thanks in-advance