I've worked with several different groups over the years. Some worked out, some didn't, some parted on good terms, some didn't. There are many ways to solidify a group. The best way? Have fun together. It can't be all serious and heavy work all of the time. Some days you just need to go out and do drunk karaoke.
It takes time and effort to build a solid group dynamic. Here are some of the better ways from the better groups I've been a part of:
Work a bonding spell together. Don't mistake this for "binding," it's not a matter of tying everyone to each other, just paving the way for open, kind communication and cooperation. It should involve some measure of protection for the budding group. I like a candle spell for this kind of thing. Everyone carves their name into it, adds protection and communication seals and charges it. Each person takes a lighting stick and lights the candle at the same time. Each takes the candle for a time to burn it.
Make incense together: Everyone grinds the herbs, passes them along to each other, and adds them to the bowl along with appropriate oils. Each person in the group takes home a share for personal use. The incense could be a generic base to which other things are added as per the intent, ceremony or season.
One of the best group building experiences for any kind of group, magical or mundane: Go out dancing together! Sharing a drink helps too- it gets your ego out of the way. Mind you, I didn't say get shitfaced falling over drunk. A drink.
Find the joy- in the work, in each other, in your world, and the drama fairies will take the bs back out to sea.