How to auto assign internal service request to resources

Summary:

We have a ERP Internal Service Request Queue. When there is a ticket in logged into this queue, we have a person to look at the queue and manually assign the ticket to the resource. It is time consuming and we have a rule to assign the ticket to resource base on category. For example below.

Category 1 - Assign to resource 1

Category 2 - Assign to resource 2

Category 3 - Assign to ressouce 1

Category 4 - Assign to resource 3

How can we achieve this? I do not see any standard function can do that. Can we use groovy script to assign the service request to resource based on category. If yes, how can we do that. I am thinking using server script trigger to assign the resource. Is anyone have any sample script that can share.