Use a concise facts summary, the proposed participants and contributor, key dates and an index of available records. Include the questions still awaiting a professional answer.
Share purposefully
Agree which documents each adviser needs and the secure channel for delivery. Preserve source records separately from summaries. If an adviser changes a material assumption, such as which entity pays or which family members apply, update the shared facts so the other analyses do not continue on an obsolete basis.
Decide what each adviser actually needs before sending anything, since the instinct to forward the entire file to everyone creates risk without improving the advice. An immigration adviser generally needs the individual's history and the proposed arrangement; a tax adviser needs the financial position and the transactions contemplated; a corporate adviser needs the entity documents and the agreement. Prepare a short brief for each stating what is being asked, what is enclosed, and what is deliberately not enclosed.
Keep a record of what was sent to whom and when. Where advisers do need to see the same material, send it once from a single source rather than allowing several versions to circulate, since divergent copies of a financial history are a recurring source of confusion that nobody detects until the versions are compared.