Straight off the van time post in the LGA Crewroom...

“In the even there are more flight attendants than seats, the driver will contact the company to send an additional van.”

“Please note that the flight attendants that are using ground transportation to get to work will be given first priority .”

And then there’s a phone number at the bottom to call if there needs to be another van sent or if it is late. For S ‘n Gs. I called the # and it seems to be an FA help phone tree.

- sounds to me like it’s a shared van but FA’s have first priority. Should a second can be needed it would be available, in theory...

If you’d like, PM me and I can send you the pic with times and the verbiage that I mentioned. (Unless that too is somehow signaling or frowned upon)