Connecting transparency for two objects

Is there a way to not have the faces in between two different transparent objects stand out like this? like have them smoothly connected? I know unioning them gets rid of this but I need them to be separate parts. Are there any solutions or do i just have to find a way of reworking my systems to allow them to be unionised. Thanks in advance!

I believe unions are the only way to solve this, but idk i might be wrong