The CDC advice is pretty clear as to staying inside your own group
Do: Stay 6 feet away from others (“social distancing”) and take other steps to prevent COVID-19
If a park, beach, or recreational facility is open for public use, visiting is okay as long as you practice social distancing and everyday steps such as washing hands often and covering coughs and sneezes. Follow these actions when visiting a park, beach, or recreational facility:
Stay at least six feet from others at all times. This might make some open areas, trails, and paths better to use. Do not go into a crowded area
Avoid gathering with others outside of your household
Wash hands often with soap and water for at least 20 seconds, especially after going to the bathroom, before eating, and after blowing your nose, coughing, or sneezing
Bring hand sanitizer with at least 60% alcohol to use if soap and water are not available.