xna - Laser Beam End Points Problems

I am building a game in XNA that features colored laser beams in 3D space.

The beams are defined as:

1. Segment start position


2. Segment end position


3. Line width

For rendering, I am using 3 quads:

1. Start point billboard


2. End point billboard


3. Middle section quad whose forward vector is the slope of the line and whose normal points to the camera

The problem is that using additive blending, the end points and middle section overlap, which looks quite jarring. However, I need the endpoints in case the laser is pointing towards the camera!

See the blue laser in particular: