Highlight Relationships in a Network 

Show the groups centered around three people at a family gathering.

In[1]:=

X familygathering = ExampleData[{"NetworkGraph", "FamilyGathering"}]

Out[1]=

Highlight the connections to David, Linda, and Oscar in different colors.

In[2]:=

X people = {"Linda", "David", "Oscar"};

In[3]:=

X highlightedgraph = HighlightGraph[familygathering, MapIndexed[ Style[Subgraph[familygathering, # \[UndirectedEdge] _], Directive[AbsoluteThickness[5], ColorData[68][First[#2]]]] &, people], ImageSize -> 400, VertexLabelStyle -> Directive[18, GrayLevel[0.3]], GraphHighlightStyle -> "VertexDiamond"]

Out[3]=

Create a line legend that matches the correct style to each person and combine it with the highlighted network.

In[4]:=

X legend = LineLegend[ Table[Directive[AbsoluteThickness[5], ColorData[68][i]], {i, 3}], people, LabelStyle -> {18, Bold, GrayLevel[0.3]}, LegendMarkerSize -> {35, 15}]

Out[4]=

Combine the legend with the graph.

In[5]:=

X Legended[highlightedgraph, legend]

Out[5]=