Rules on COBRA regarding adding wife and son to coverage

i recently resigned from my job and my new job does not offer a Small Business so for the time-being, i will be signing up for COBRA from my old job. my wife and son have been overseas for the past 3 years and were not living with me so i did not bother to include them to my previous eisting group health plan (BCBS MI). my wife and son plans to join me soon, probably within the month. to complicate matters, my wife is pregnant. BCBS have advised that I can only add them on in June or July during open enrollment. on top of that, she still needs to go through the 6-mos waiting period. this would obviously mean she won't be getting any coverage well past her due date. the question is: is there any other way of going around this? can I add my spouse and son directly to COBRA on their date of arrival without waiting for open enrolloment?