Task report grouping with an IF statement ("No Value" name replacement)

Hi all,

I have a task report that is grouped by assignedTo:name. All the rows are grouped by assignee name except for the "No Value" group of tasks that are assigned only to a team or role.

I would like to highlight this particular group by changing No Value to " Hey, you guys need to assign these tasks!" instead of "No Value", or something like that.

I've tried an IF statement right in the grouping but couldn't figure that out.

I've tried the below three calc field attempts on a task form to maybe group by that but keep getting "Calculation Not Valid":

IF({assignedTo}.{name}="No Value",ABCD,{assignedTo}.{name})

IF(ISBLANK({assignedTo}.{name}),"ABCD" ,"assignedTo:name")

IF(ISBLANK({assignedTo}.{name}),"ABCD" ,{assignedTo}.{name})

Has anyone done this successfully? it seems easy until I tried to do it. Am I even thinking about it the right way? It's probably just a syntax problem but still.

Thanks