There is an article in The Age today called Backlash Feared Over Uni Students' Culture Divide. The article claims that many Australian universities are dependent on funding from international students and that there is segregation within universities between international students and domestic students.
I have finished university now but while I was there I did indeed notice that international students stuck around with other international students. But that is what was expected. Many of these international students may have been to the same schools together and therefore they know each other well. It makes sense for people who know each other well to continue to be together.
I came from a high school that is under-represented in the tertiary sector, so when I was at university I didn't see anyone who went to the same school as I did. This meant I had to make new friends. Roughly half were international and half were domestic. The main problem with some international students was shyness.
The article claims the following: "Local students tended to work off campus and were not active in student life, while international students spent most of their time on campus, generally in the library, Professor Simon Marginson, of Melbourne University's Centre for Higher Education, told The Age." So then the problem may not be a conflict between international students and domestic students but a conflict between those who study a lot in library versus those who spend much time working off campus.
The article also talks briefly about Voluntary Student Unionism (VSU). It claims that student union groups could organize events that attempt to bring students together but they simply don't have any funding because, when students have the option not to pay student union fees, many choose not to. If students unions are not organizing events then the university administration itself could organize events. If student do indeed want to be involved in social activities then universities can generate more demand for their services by providing these activities. More demand means they can increase prices and get more revenue.
What I really suspect however--and my suspicions are based on observations of other uni students--is that most students nowadays don't care about social activities. They just want to go to university, get their degrees, get out, and get a job. This seems to be the behavior of just about all students, both international and domestic students.