Laravel：使用关系表加入

I have 3 tables:

members:
  member_id 
  first_name
  last_name

groups
  group_id
  group_name

members_groups:
  member_id
  group_id

A member can be in multiple groups while a group contains many members.

I have a lot of record in all tables and some joins in my query to get the member according to the input parameters. I need to output the member name along with his group names divided by comma, so have to add one more join to add member groups without iterating each member or load group model to get its name.

See the relative code below:

$members = $members
   ->leftJoin('companies', 'members.company_id', '=', 'companies.company_id')                 
   ->join('email_addresses', 'members.member_id', '=', 'email_addresses.owner_id');

Please advise.

Thank you.