Mod for improve admin auto assign

[sunlight76]

I would like to autoassign ticket to administrators ONLY if there is no user with autoassign for the selected category, is it possibile ?

Example:
I have many users, only one (User1) is assigned to category A

First ticket sent with category A is auto-assigned to User1 (correct)
Second ticket sent with category A is auto-assigned do Admin1 (this is not correct: it should be assigned to User1)

Klemen stated that he do plan to improve the auto-assign functionality, but I'm in a sort of urgency.
Anyone could help in find where to change the code?

thanks