You don't need to have made the decision before you start — but you will need to make it during the process. And a good branding agency should push you toward it rather than help you avoid it.
The reality of multi-audience brands is that the brand itself cannot serve all audiences equally well. Trying to build a visual identity, a verbal tone, and a homepage experience that satisfies five different stakeholder groups simultaneously almost always produces something that underwhelms all of them. It's not a failure of execution. It's a structural impossibility.
What works instead is distinguishing between who the brand is for and who specific pages, products, or journeys are for. The brand — the core identity, the primary positioning, the look and feel — should be built decisively for one or two audiences. Other audiences can be served through tailored content, dedicated landing pages, and specific messaging tracks without requiring the entire brand to speak in multiple directions at once.
This is one of the hardest conversations to have in a branding project, because it requires leadership to make a call that some stakeholders will be uncomfortable with. A strong branding agency doesn't smooth over that discomfort — they hold the line on it, because the alternative is a brand that means nothing to anyone.