Combine Multiple Splines into One

[abdullahsorathia]

The above image is a sample of my project. Am creating a road map using Rectangular Splines.

There are approximately 2000 such rectangular spline.

As seen in the above image Stage 1 is the initial Structure and stage 3 is the final Outcome

The thing I am trying to achieve is I want to convert The spline in one and Remove the inner edges to Optimize the Game.

 

Is there any way to do that. Doing manually is very tough and there are nearly 30 level each containing 2000 splines