Bombardier work at Belfast Bombardier integrated Belfast to work on C series, and Global jet seamlessly. This integration continued when Spirit took over.
While a220 work can be separated, the workforce separation is not that easy. However Workforce will have to be separated as AB only bought a220 work.
Bombardier might be better off letting someone else buy Global work. But no will want to buy a loss making business. Plus pension liabilities, debt etc.
Either someone gets paid by Spirit to take the Global work or bombardier takes it for $1 plus extra for liabilities. Just like AB did.
https://www.irishnews.com/news/business/uncertainty-for-belfast-aerospace-workers-as-airbus-takes-over-part-of-spirit-operation-6AOCJTL3HVEYJICEXO3M2FZ3HY/
https://airinsight.com/the-boeing-spirit-aerosystems-deal-is-expensive/