My fraternity has a book with all the addresses of the more than 30,000 members all over the world. So whenever I travel, I could theoretically call them up and ask if I could drop by. Moreover, there are a lot of Alumni groups all over the country and it is a custom that you show up at their meeting place when you move there.
For example, two brothers of my chapter now live in the States and we will be three soon.... We are definitely going to meet (at the latest, when we are going to represent our fraternity in our official uniforms at one brother's wedding, next summer in Mass.!
http://www.kdstv-bodensee.de