Sync User Checkboxes to Mailchimp

Dear People from Mailchimp User Sync,

I have installed the Mailchimp & Mailchimp user sync plug-in on my WordPress website.
I am able to send my user data to mailchimp and it works great!

Currently I am using Buddypress & Buddypress custom profile fields and I am able to send custom profile fields to mailchimp in the following way:

‘$data[‘***’] = xprofile_get_field_data( ***, $user_id );

For single line fields this works great and i dont have any problem.
But for multiselect boxes / checkbox options it doesn’t work.

I was searching for a option to fix this and i found out that Mailchimp groups might be the solution. But i am not sure how to make this work.

Can u maybe help me out here, that would help me a lot.

Regards,

Nico