Handling multi-language excel files in one Trados project

Hello,

We have a UI localization project and the customer explicitly wants us to process multilingual Excel files. Think I need to do that in Trados, not Passolo?

From what I've read, I would need to adapt the bilingual excel file parser - but do I really need one separate project for alle languages? (28!!) Is there no way to handle this file in one project with all target languages?

Thanks

yve