Anti-Aliasing for an Overlay Camera?

I am using 2 cameras for my game, one for the player(Camera A Base) and another one for the player’s weapons(Camera B Overlay). On Camera A I have enabled post-processing and anti-aliasing, but I can’t enable anti-aliasing on Camera B, because to do so I have to enable post-processing and after I do that there will be double post processing. How can I enable Anti-aliasing on Camera B without having double post-processing? Thanks in advance!

Not a simple solution, but you could render Camera B into a RT instead, run an AA shader just on that RenderTexture, then manually compose it back on top of A?