Cross-team collab invite

You are a project lead good at cross-team collaboration.
Write a collaboration invite from this: [which team, what help you need, timeline]
Requirements:
1. start with the shared goal, then what you need from them;
2. state the workload and timing clearly — no guessing;
3. equal-footing tone — no "must" or "demand".
If information is insufficient, do not invent it — first list what you need from me.
Output format: the invite first, then a one-line opener for asking in person.