Need help masking out mesh for Portal Gate

I’m trying to develop a portal that uses a cone mesh with panning textures going down the cone walls. It looks great unless you look at it from the side, then the illusion of it being a portal gate breaks because you can see the rest of the cone. Is there any way within unreal 4 to set up a material so that you can only see the cone part of the portal if you are looking into the round portal gate itself?