Build Dictionary from 2 tables

Hi I have a link and a node table as follows. I would need to create a number of lines based on the nodeid and also the node type. Where type=vertex, I would only add a vertex to the line to represent change in direction.

 NodeID   
 Coords
 Type
 A
x1,y1 
Valve 
 B
 x2,y2   
Valve
 C   
 x3,y3
Valve
 D
 x4,y4
Vertex
 E
 x5,y5
Valve

 FromNode
 ToNode
 A
 B
 B
 C
 C
 D
 D
 E

Expected Output

Line 1 coordinates: (x1,y1), (x2,y2)

Line 2 coordinates: (x2,y2), (x3,y3)

Line 3 coordinates: (x3,y3), (x4,y4), (x5,y5)

With C# I would like to be able to loop through the 2 tables, and build a dictionary (or similar) with line number and coordinates, so that I can go and then create the geometry for the lines.

Any ideas how can I go about achieving this?

Thanks