How can I merge multiple source xlf file for alignment with one target xlf file?

Hi!

I have multiple EN xlf file and I need to align them with one ES xlf file. Is it possible to merge EN xlf file into one and the align it with the ES file?

I created a project in Studio but SDLXIFF Split/Merge tool does not give the option to merge.

Can you think of another workaround?

Thank you!