Are Non-Compete agreements between companies legal?

I work as an engineer for a global telecom company and recently my manager announced that he is has several job openings for additional engineers, but is having difficulty filling these spots. He explained that there are agreements between several of the competing telecom companies not to hire specialized engineers unless director or VP management at both companies agree. Because of the paperwork and time delay for approval (months) he is limited in who to interview and is passing up qualified candidates.

My assumption is that he is telling the truth as he understands it from HR, but it could also be a ploy to cow employees into not leaving.

I find it difficult to classify what this scenario is since it would no strictly qualify as no-hire or non-compete if there is an agreement between companies and a candidate does get hired. This sounds a lot like the DOJ case against Google, Apple, Intel, etc settled in 2010 (case 1:10-cv-01629 ) but that case focused on "cold-calling".

It's a troubling thought to know that new members to the team may make the same salary as me, but be far from qualified for the job at hand.

Even more so is the thought that if I decide to look for a new job that it may be contingent on if my current company agrees.

If what I described is true, is it illegal? If so would it be antitrust, discrimination, or other?

What steps can someone take to verify and remedy this?