I have done it - OKW does not have a problem - we were going together - but some people get on my nerves if I am constantly with them - they were close to the HH (which is what they wanted- building 11) and I was in building 55 - my favorite....
we meet a couple of times - that was more than enough for me.
find out what your sil favorite part of OKW is and stay as far away as possible -