Family Issues Support Group
Family issues is a huge range that go from minor conflict to major misbehaviour and even abuse on the part of individual members of the family occur. Whether you feel you are in a dysfunctional family or you're dealing with a very specific issue, this is the place to talk about it and find others who might be going through the same thing.
First off I would stop the group gifts, do what you want alone. Then if you want do the cakes but only if you want and if it's for your parents make them bring something.
Being included is tougher. It sounds like you really don't like your brothers so why do you want to hang out with them? If you feel they are excluding you then confront them. I'd be very mad and yelling at them that it's ok for them to expect you to invite them for birthdays and holidays but they can't take the time to call you? If he talks to everyone else why couldn't he call you?
Grown up siblings are tough. Some stay close, some go their own ways and some become enemies. And both parties have to want the same thing so we don't always get what we want. If it's important to you I would call both brothers together and tell them how you feel.
I think that's okay, we all work to save for retirement but others spend a little more freely which they just might resent a more cost effective approach.
Not all families stay close as the years go by. Everyone just gets caught up in their lives. I would talk to them like Tigg stated and see where that takes you.
You have your priorities straight and are successful as a result. Them??? Not so much.
I'd stop looking for their approval and know that you are fine the way you are. They just don't want to be reminded of how inferior they are.