Check your state, county and city executive orders and other mandates.
It's something you should be familiar with anyway... but there's a fair chance a government order at one of those levels will prohibit the meeting.
You are looking in 2 areas: General, and Employment.
Obviously most of us think about the rules on social gatherings, and any such rules do apply. In most states, 5 friends getting together is legal, at least outdoors with social distancing.
But this is an employer function as part of a job - and that brings in another chapter of regulations. A few examples of such regs:
Obviously those last two conflict with a sit-down meeting in a restaurant. But what do you do with that??? What's the regulation issuer going to say about that? Since my advice is "check with your state, county and city", that's a good thing to ask them.
But I don't see too many saying "sure, hold an unnecessary meeting and suspend precautions". I think most will say "No, the rules preclude lunch meetings". Again you must ask.
Further, "doing it anyway" can be as serious as a misdemeanor; and while early on, the governors were making the rules fairly toothless, of late they are cranking up the penalties.
You also have civil liability (lawsuit) if you pass on COVID to another person. Even if a governor waives criminal penalties, that does nothing to ease the risk of a lawsuit if someone contact-traces their infection back to such a meeting. The liability is both corporate and individual, especially if the individual apparently lied on a COVID screening form.