Good Morning Sebastian.
What you want to accomplish then, as this now appears, is more than desinged in the software sofar.
And in general, for situations like this, where a user asks for a change of behaviour of the current release of the product, I can propose to add an Idea in the Communities.
So, as to this threads's question, I encourage you to open an Idea in the CA Service Catalog Community.
To get your Idea voted for and reviewed by us there after.
For us to see whether it is possible to get this functionality implemented in a future release of the products.
This is the status as to my knowledge.
Should some one else in the Community have an answer for you on this, then for the better.
Thanks in advance for your efforts on this and kind regards, Louis.