Hi Sofie! I know you from twinstuff.com ;)
There is a local Mothers of Multiples group and they organise playgroups twice a month - it resumes again in September (since so many people go away for July & August).
Sounds like our twins are nearly the same age - mine will be 21 months in August (gg)
http://moms-hongkong.com/
Look forward to meeting you in person!
ANd back to your question, yeah there are plenty of twins living in the South side
