Unfortunately bullying like this is not uncommon in the NHS, but that doesn't mean it should not be challenged. Absolutely you and the other students MUST make a FORMAL complaint. You should do this jointly as a group and have each others backs.
If you all write your own experiences ( with dates, places and what exactly was said/ done etc) of the bullying and then show how they overlap, ( as they will), then no one person can really be singled out for making the formal complaint.
Hopefully this will make any backlash from the bullies non focused, as well as highlight exactly what bullying behaviours have happened, to whom and when they've happened.
You should all be members of a union (if not, then join asap at student rate). You need to tell your union/s what has been happening, and ask for their help and input, as well as their presence at any meetings with lecturers or mentors in placements about the bullying.
You also need to (as a group) request that during the formal complaint procedure, non of you are in a placement with or have to collaborate on a project with any of the named bullies.
Basically, get all your ducks in a row as individuals and as a group, then ask for a formal meeting to raise a formal grievance / complaint against each individual bully individually and also as a collective group of bullies.
I hope you get this appalling behaviour stopped and that you all get the full support of the teaching staff, the placement staff and the union/s to help you do it. NONE of the bullies should EVER be in a public facing job where they have access to sensitive information and access to vulnerable client groups.