Run as many legal entities and currencies as your group needs, with date-effective FX so every estimate and actual lands in the right books at the right rate.
Every legal entity carries its own books currency; every rate is date-effective; every line prices at the rate that applied when the work was quoted.
Each entity keeps its own currency, terms and numbering.
FX is looked up by the quote date, not today.
Role-based access scoped to each legal entity.
Every entity, every currency, one source of truth.