[Terretta]

Because of the use of the slash in the original post, I suspect he meant this as:

    ((junior||front end)&&(back end)) developers.

I took it to mean some of the developers in question would be senior (non-junior) backend developers.

[splendidfailure]

I like your interpretation. If for no other reason, it would seem to back up the idea that the OP is merely bad with words and was in fact describing the current composition of his team (a team diverse in gender, ethnicities, levels of experience, etc)