Not necessarily. Czech uses masculine plural for mixed and even unspecified groups as well.
And I forgot about "handsome", thanks for reminding me. Added.
So to answer your question, "My jsme hezcí" can be said about a group consisting of men thinking being handsome, girls thinking being beautiful and possibly some really cute people.
hezcí - I needed more than the sound to get the spelling. I mean we knew of this consonant shifted word. And the vocab is small and so that is helpful at this very early level. But, though Czech is said to be phonetic, my ear has not got far (enough) recognizing Czech words by sound. I look forward to better language memory.