Your company can be exempted from the job advertising requirement if you need to transfer staff from an overseas branch for a short-term contingency (i.e. period of employment in Singapore is not more than 1 month).
However, the Employment Pass holder will not be eligible to renew the EP nor apply for a new EP for 3 months after the expiry of the previous EP.
If you need to bring in foreign staff for a longer duration on EP, you must meet the advertising requirement.