saving assembly as an combine part to import it to another programe

Hello All,

I have a sub-assembly which has a lot of parts. I wanted to save it as one part. I used (save as) ---> part--> All components. Then I converted it to parasoild. However, when I imported to Adams software. I found that it is several parts there not as one part. Is there a technique that I could save it as one part in solidworks, and when I move it to ADAMS it will be also one part.

Best wishes,

SolidworksAssemblies