The “foreign community” thing mentioned in Storti’s book  make me think of the Chinese church here. I have seen American missionaries’ foreign community in several cities in China. They live in the same or close complexes, and their wives always meet with each other and having things to do together. However when I came to US this time, I also found similar things in Chinese churches here. The Chinese churches are not only a spiritual home, but also a cultural home to Chinese people.
On the positive side, we can see that the Chinese churches are doing their best to host new immigrants and also lead them or a portion of new immigrants into Christ. The atmosphere in the church is very friendly and people are very willing to help each other. This kind of willingness to share and help is very rare even in American and house churches in China.
Is there any negative side? From my point of view I found following two:
1. The churches are very reluctant to have influence in local community and local people. Even there’re many US citizens in Chinese churches, I’ve rarely seen them talking about cultural mandate in US, not even mention social justice and mercy in US.
2. The new immigrants coming to Christ partly because of that they are afraid of losing the connection in this “foreign community”. Once they don’t need it, e.g. back to China, they will leave the faith as well. As a house church leader in China, I have seen that only 10% of returnees continually go to church.
There are many Chinese immigrant churches around the world. China has such a large oversea population so that Chinese missionaries even don’t need to study another language and can work in any country. But be aware that if mission work is only setup in a foreign community, it’s not a true local church.
 Craig Storti, The Art of Crossing Cultures, Intercultural Press, 2007