R和igraph：创建一个图表，显示哪种顶点属性在它们之间有边缘

So I have got the following problem: I have got a rather large network which contains information about the personal connection between people. One of the vertex attributes is their town of residence. I now want to see if there is a connection between people from different towns. The kind of result I would like to get is a plot which represents these linkages. It might be the easiest to show an example of what I was looking for:So I have got the following problem: I have got