I'd create a process action to replace assignment action and as part of that process check the group concerned. You can then use another automatic action to change the response level to the 'right' one.
However you might also want to look at one group (a serviccedesk) owning the main issue and then allocating a task to the other group and putting an OLA against that task. If an incident gets reassign too many times, the poor old response level will get recalculated a lot. That isn't a problem, but which response level would the customer expect might be unclear.
"You can then use another automatic action to change the response level to the 'right' one. "
How i do this? Have i make a calculation for this step? We have some response level in dependency from the current impact and urgency. So have i make a calculation to choose the right one, or is there a backgroung handling about the response agreement?
If i do change the response level by automatic action, have i change the response agreement too?
You'll need to tie a few things togther. Firstly you can change the value of an attribute using the method laid out by Stu here :- http://community.landesk.com/support/docs/DOC-12557 Ok that one is for colour but the same method applies.
Next in the 73newfeatures.pdf guide on your documentation CD there is an example on page 92 of calculating a priority and I'm guessing (but I don't know), that you could use the same method to calculate your response level. Alternatively you could put the same attributes you are using on the main incident to set the response level using the response agreement on your windowless action and let the response level functionality take care of the calculation. You'd need to make sure something changes on that window to make the response agreement kick in, but without knowing a lot more about how your response agreement is done, I wouldn't know whcih attributes to suggest. If the response level you want is 'known' so you can set it directly in the process by looking the group on the assignment that would be the easiest method.
If you change the response level yourself, you don't need to change the respose agreement. You just make sure the SLM handler isn't recalculating the response level by making sure that handler isn't on the window.
Now to be fair what you are trying to do isn't that easy and the devil will be in the detail. If all the about sounds a bit hard (and I accept it isn't a step by step method), then if possible I'd get a LANdesk type person in to do this and workshop the method with them so you have the skills for next time.