Mask mesh renderer outside sprite bounds

Hello. Made a couple of mesh particle systems, one of which, creates meshes with spritesheet textures, to represent wounds/blood stains on the sprite that appear at the point where it was shot. It is the "WoundParticleSystemHandler", child of the "wounded" sprite.

https://imgur.com/a/trsb3Qz

The problem is that I want to mask/occlude the parts of the blood that are outside the bounds of my sprite (to the left of the yellow line I've drawn in the screenshot for example).

I can't do it with a sprite mask though because the WoundParticleSystemHandler has a mesh renderer so there is no option for them to be "visible inside the mask" like there would be with a sprite renderer. Any ideas?

 

Bump - rephrased the question.