Group Attribute Values

Hi there, 

I am looking for support to create a specific chart that separates out groups of values from the same attribute as individual bar on a bar chart.

Example:
I have an attribute called “Assignee” that represents a user that was assigned to a given alert.
I want to create a bar chart that compares the volume of alerts assigned to 3 specific users from the Assignee attribute to 2 others from the same attribute.
Ideally, I would be able to label Group A (Assignee 1, Assignee 2, Assignee 3) vs. Group B (Assignee 4, Assignee 5).
Is this possible?