Doc, If you're planning for Goa, it's prudent to stick to South Goa. Whilst North Goa is where the action lies, a reunion is meant to savour the present moments and cherish the old memories. So it is apt to stay at a place which has some tranquility and a perfect ambiance to mingle with your buddies. But if sightseeing or beach hopping is on your mind, I wouldn't recommend South Goa.
These are the luxury properties that I can recommend:
Goa:
Dona Sylvia Beach Resort - It is a 4 star property (Though they claim it to be 5 star, which it isn't) right next to the white sands of cavelossim beach. The property is spread across 20 acres and has independent cottage style accommodation. You can read more about it on tripadvisor and on their website
http://www.donasylvia.com
I stayed here in June this year and loved it.
Grand Hyatt - A 5 star property at Bambolin beach. Awesome rooms, especially the beach facing ones. Service is quintessentially Hyatt and food is great. Though it can accommodate large groups, it is more suited for destination weddings and conferences kind of crowd. Nonetheless, the property is worth checking (
https://goa.grand.hyatt.com/en/hotel/home.html). I stayed there in August 2014
Few other places that I've heard good reviews, but haven't stayed are:
Park Hyatt (Recommended by my close friend), Vivanta by Taj (at sinquerim beach/Fort Aguada)
Kerala:
If you aren't too rigid about a beach property, I can surely recommend The Zuri at Kumarkom. It is nestled at the banks of Kumarakom lake in the lush green surroundings and an awesome place for family gatherings. Their cottages (kerala style villas) , are very very good. The hospitality is top notch. I went there in monsoons couple of years back and loved every bit of it. (
http://www.thezurihotels.com/lake-resorts-in-kumarakom/)
Leela at Kovalam beach. A wonderful property facing the sea. Though I haven't stayed here personally, but have heard quite a lot about this property. (
https://www.theleela.com/en_us/hotels-in-kovalam/the-leela-kovalam-hotel/)
Additionally, since someone mentioned Pondicherry/Mahabalipuram, I can surely recommend Vivanta by Taj, Fisherman's Cove at Cavelong Beach, ECR Road (It is close to 30 kms from Chennai). Very nice beach property and some great deluxe delight rooms and cottages. I stayed here last month, ample food choices, sea facing restaurants, etc. Would definitely recommend ! (
https://vivanta.tajhotels.com/en-in/fishermans-cove-chennai/)
Make sure you read tripadvisor reviews of all the properties and bargain hard for the group booking.
Have a blast!