Need to create data visualization based on old assignment group value

[priyakosana]

A single data visualization, for every HR case that is assigned to GroupA (or was assigned to GroupA at some point), shows the HR Case number, Current Assignment Group, Previous Assignment Group, transfer timing metrics (transfer to/from date and time or time each group had the case), and cycle time (how long the case remained open before resolution). 

[priyakosana]

I've tried creating a new field in the HR Case table to store the previous value. But the catch is that they want the report to show the record at any time it is assigned to GroupA, just not before the value changed. In the whole cycle, when it is assigned to GroupA, it needs to be shown in the report.

To show the records assigned to GroupA:
GroupA -> GroupB ✅

GroupB -> GroupC ❌

GroupB -> GroupA ✅

GroupA -> GroupB -> GroupC ✅