Hope they recover and are ok.
I have ridden motorcycles for many years and riding in the rain is no treat.
Good tires and careful riding practices are required to get where you are going safely.
I have been in many circumstances where police motorcyclists have escorted the line of motors. I havent been impressed by the way they do this. Mostly motorcyclies are used to get ahead of the line and block traffic on intersecting streets. To do this they ride at the front of the line and drop off and hold up the traffic at these intersecting streets. After the stream of motors passes they get back on their bikes and sometimes travel at dangerous speed and pass in dangerous places to get back to the front of the line. Often if they are caught by oncoming traffic they will duck into the stream of the assemblage without warning.
Being a motor officer doesnt make anyone immune to the hazards of all motorcyclists and if proper caution isnt taken they can end up on the street, like anyone else.
St. Mary's County has one officer I know of who will probably be retired or maybe already has been ,as the result of one of these escort details. He went down while escorting a funeral in Charles County. I dont know any more of the details but escorts by motorcycles can be dangerous . On wet streets that is multiplied many times over.
Extreme caution must be used when passing the escorted line as many times these lines are formed by inexerienced bikers who think they have learned to ride but in reality have little experience
The way I read this the accidents were all individual accidents and not one bike hitting the other. If so it is certainly strange that 3 riders had crashes in the same cortege. You must adjust your ride to the conditions and not be overconfident. Slick roads will get you and in the fall the falling leaves add to that. Somebody needs to evaluate what happens and make some changes in the way these things are done.
I have seen them doing things any other motorcyclist would get arrested for.