How do I set tile map tile to other tiles around it?

I want to make some of my tilemap tiles join together.

I have this as my tilemap, with each tile can be used for different possibilities of surrounding tile.

Is there an easy way to go about selecting the tile to use given the 8 surrounding tiles?

...or should I just use one tile that can tile nicely?

Someone posted this at some point and guess that is what you are referring to? Which is the best way to do it I think.

http://www.saltgames.com/2010/a-bitwise-method-for-applying-tilemaps/

Otherwise you could hardcode it yourself, by just going through the tilemap, tile by tile and setup all the rules you need. But again would use the method in the link.

Here's a thread with an example of the method nimos100 linked to:

This tutorial does something similar, but is for tiles generated by autotilegen

After reading these I think I'll use the second idea of not having the tiles join as I want to have many tiles and the number of connecting tiles would be too much.