Apply sort on specific index


I have two indexes on my setup - Index-A and Index-B. I want the results of the query to be sorted. The field on which I want to sort (say firstName.raw) is present in both the indexes.

My question - Is there a way by which I can sort results only from one of the indexes (say Index-A) ? I don't want to sort results form Index-B.

SideNote-1 : I wanted to do the same with filters as well. Which means, I wanted to apply the filter on a field only on results from one of the indexes. I was able to do this using Indices filter - How can I do something similar for sorting ?

Thanks for your help!