If you need work in several markets you could appoint a "multinational" (ie a network with the same name over every door), create your own ad hoc network or use an existing one like IPREX. All three approaches have advantages. Here are ours:
Global: We have high quality companies - not branch offices - in major markets worldwide, so we are on the ground where our clients need us and where our cultural diversity is a business advantage. Where we don't have partners we often have affiliates
Channel-neutral: With no silo mentality, we focus on integrating strategies, techniques and channels that hit client targets
Professional: We work to high professional standards using modern management processes, and we police them
Flexible: We are set up to deliver everything from a quick project to a major international program
Fast: With no institutionalized chains of command we are quick off the mark and hit the ground running
Effective: Our working systems promote seamless program management and deliver results our clients can measure
Value for money: With network operating costs less than 0.2 percent of revenue, IPREX clients do not pay fees for global infrastructure they don't use - or for remote shareholders' profits.
We suggest that you see if we have offices where you need work, then pick the most conveniently located partner to act as lead. They will put together the team you need.