Gopal,
I have to ask, with no script, what will the agent be shown?
You mention not wanting the agent to disposition the call (at all)? From what you say, can we assume that the agents are leaving messages on the Answering machines (or is this automated?)
Based on what you are saying, you could have a single disposition button (essentially "Next Call Please") and then use a Disposition Policy to (re) dispositio the call based on Call Analysis.
Alternatively, with a Custom Script, you could automate the "Next Call Please" based on the call disconnecting, so the agent doesn't need to click anything.
We can probably figure something out for you, but I am curious as to the use-case. The Wrap-Up codes are typically used to perform analysis on the Campaign / Agent and the data you would get from this kind of setup would more or less replicate what you get from Call Analysis information.
Sorry, but I'm somewhat confused here!