If there is no option than South, you can have an entrance in SE. Don't have the office in extreme SE corner, leave 1-2 foot for the entrance.
If you can share the office, plan and other details of the property, better.
The best entrance for office is in East to East North, South to South-South East. South East direction means Corner of South and East. There no place for entrance. South to South-South East such as underline a space under following this picture;
Above Apace which is dabble marking are the best space for entrance. These entrance are life of success in every ways. Thy helps us increasing business, name and fame also.