@Aayush Sah (IND) , I'd shared this on your SO thread and also was expecting your reply to my private comment here.
You may try to break that down during pre-processing and assign each 'tier' of the hierarchy to a different field, as below:
Top_Level_Field=”a/b/c”
Next_Level_Field=”b/c”
Bottom_Level_Field=”c”
Typically, each facet tier can have different values but you need to have a pre-determined hierarchy depth.
Kindly let us know if you have any further questions on this.