Mesh transition techniques

Hi all,

I would like to make fine mesh in the critical area of the model and coarse mesh in general areas. I have seen one model how this was done using method I would like to get to know- see the attached figure.

It seems that on the shared edge 2 surfaces are connected but with each second node unconnected. Does anyone know how to do this? It is important that 2 surfaces remains connected. 

I have read about mesh transition techniques in Hyperworks Student Guide but it does not say anything about this method.

Thanks.

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