Cross-Domain Tracking Strategies for Multi-Brand Setup

Guidance needed on cross-domain tracking and multi-brand setup Hi everyone, I’d appreciate your help with a setup challenge we’re facing. Our company operates several brands, each with its own website (e.g., alpha.com, bravo.io, etc.). Some features—like our website builder—are shared across multiple brands and embedded within their respective sites. We also have scenarios where a user’s journey within a single brand can temporarily cross into a different domain. Mixpanel identifies users via domain-based cookies and device IDs, which leads to two challenges: 1. Single-brand journey across multiple domains Here’s a simplified user flow: Page visit on alpha.com >Page visit on alpha.com/page2 >Page visit on alpha.com/page3 >Page visit on bravo.io/page2 All of this is a continuous journey from the user’s perspective within alpha.com and the user is identified under alpha.com, but because of the domain switch, I assume Mixpanel treats it as a separate user or session. What would be the recommended way to track this as a unified journey? 2. Cross-brand feature analysis We have shared products, like our website builder, that are embedded into multiple brand domains. Ideally, the website builder team would like to analyze usage across all brands in one Mixpanel project. We can assign a global user ID across brands, but we’re unsure whether this would lead to identity issues and multiple other. The clean approach would be keeping them separated and analysing each feature in the context of the website they're embedded, but I can understand how usefule it would be to analyse a let's say a funnel conversion for the feature and then break it down by a different domain to identify differences Should we send all events into a single project or keep them separated per brand? What setup would you recommend for a clean, scalable solution? Is there a concept of Portfolio (like ion Amplitude) ? Thanks in advance for your guidance! Best, Luka