I'm sure there is a patron saint of ED somewhere among the 10,000. :O)
All the Franciscan groups would make another, as would Benedictines, Carmelites, etc. And I guess the last thing to say is that all these are approved ways of being Catholic.
Why should there be any groups with differing orders, rules and regulations? If you were to transgress the orders rules, wouldn't they kick you out?
Maybe if there were persistent transgressions, but that wouldn't necessarily have any effect on your access to the sacraments. But it's a serious thing to be kicked out. I think in most cases people are not so much kicked out as they ask to be released from their vows.
In my case, I promised to be sorta like a "novice" for a year, and now I am finishing the first year of my temporary promises, to which I am bound for 3 years. Then I can either quit, ask for one more year to make up my mind, or promise to keep the rule for the rest of my life.
It's interesting here that Dominic said breaking the rule of the Dominicans was NOT a sin (even though obedience is implied in the promises we make) and that if he found that any friar was saying breaking the rule was a sin he'd personally go through all the books of the rules and scratch the rules out with his knife. This was because the main driving mission was evangelism and preaching and sometimes that doesn't make for a well ordered life.
I think, as a generalization, one might guess that Catholics are more about community than a lot of Protestants are. And so, while I know of quasi-"religious" groups among the Protestants, like Taizé, from the time of the desert fathers, through Benedict and up to Mother Theresa Christians have formed groups around a shared ideal or mission.
Also groups, "orders" provided needed services for diocesan bishops while maintaining a kind of credibility and a degree of autonomy. Once Francis and Dominic had established their orders reputations, they were given permission and even asked to go into various areas and carry out their ministries which were too demanding for the indigenous clergy.
It's sort of trivial in comparison, but in our chapter of lay Dominicans is a general practitioner.. She gets a lot of complaints because she will not prescribe contraceptives, only prescribes viagra, etc. for married men, and so forth. I know it means a lot to her that she has a small group of "brothers and sisters" that she can call on for prayers and support or to whom she can vent when the fertilizer is flying thick and fast.
Or here's something about the brotherhood in orders: You know of this deal the Pope has just done where Anglican groups can come into the Church and maintain much of their Anglican identity? Well, about a year ago our chapter was contacts by our former pastor who was by then #2 guy in the Eastern Province (eastern US) of the Dominicans. We were asked to pray daily for 40 or so days for God's will to be done in some enterprise the nature of which we could not know.
When the dust settled this Fall, we were told that a Dominican who is an archbishop and a muckety muck in some Vatican bureau or commissariat or whatever was working with PapaBenXVI on this whole thing. So he had requested the prayers of literally hundreds of Dominicans around the world.
Anyway, why do people join clubs or benevolent associations or things like that? Something like that contributes to the formation of orders.
Mother Theresa had people coming from all over the world to Calcutta to live, pray, and work with her, and some decided that's what they wanted to do for the rest of their lives. So, "Missionaries of Charity" with 4,500 women around the world, giving their lives in prayer and service. Pretty cool.
Tired, drugged and sick, and hoping I'm making sense and being helpful. And sometime we will share adult beverages and consider with more attention the whole decree of erection question. Right now most of my considerations are not suitable for this forum.