This would be incredibly annoying.
If you are comfortable with asking the questions of HR then do so.. it is your right to not have to deal with this at work.
Or
Rather than stir the pot with religion, perhaps create a humanist group. That word is more palatable to the thumpers.

You are right. Religions should not be mixed with work, but I would take this as a great opportunity to ask pertinent questions and see how they like them apples.

I run multiple companies and while I have specific code of conduct rules against discrimination for or against religion, sexual orientation, politics, and unprofessional or "sexual" behavior while working with other members, partners, or clients.

I generally tell all involved to simply not discuss such topics while on the clock or in group settings. While some may imply their religious points of view and what it references. I make it pretty clear that being "preachy" is not allowed nor wanted by most of our membership and clients. It is unappropriate to drone on and on about your sportsball or your love of a hobby to those who didn't ask for it. Let alone doing so while on the clock.

Can't you opt out of this "group"? It seems bizarre that you have to see posts for something you're not a part of.
Tell your management you're feeling harassed by the involuntary proselytizing you're being forced to read.

Just ignore them ... they are the clueless.

Form your own group with secular positive sayings.

Dude at work the other day wore a "Y'all need Jesus!" T shirt. I wanted to be a dick but I got to work there lol.

Are you able to unsubscribe from that group's updates?

Just scroll on by...Why waste the energy worrying about other’s beliefs?

It’s simple: Do not go on Facebook.

Ask your IT department for a way to block the emails from this particular set of people. And complain to HR. What is happening amounts to preferential treatment based on religion, and it should not be happening.

That would piss me off as well. I see your options as being three-fold.

1. You can tolerate this, remain quiet and keep the peace.

2. You can complain to management that you feel harassed by this and make the argument that the workplace should be religion and politics neutral.

3. You could start an atheist group and claim equal time be given to promote your views.

Obviously the first option is the easiest while the other two could come with socio-political consequences. It's up to you which option works best for you.

I understand and agree with you. It should be neutral, but that's hard to get. Quit the damned "Workbook" if you can or buy a few stress balls.

Do you have an hr department or a compliance office where you work? Register a complaint with whatever you have. If you have neither, complain to either your state DOL, or find the nearest federal DOL office, and register complaints there. You may suffer retribution from your employer or fellow employees, and if you do, document it and sue. ?

I understand your annoyance, and I would prefer not to see that crap too; so why not just turn off their notifications.

Does your place of employment have an HR Department?
If it does, I'd be making a personal visit to the department head.
Straight to the top, do not pass Go, do not collect $200.