Fields of relations tables

Hi,

Let’s imagine we have these tables:

users(id, name)

groups(id, name)

users_groups(user_id, group_id, cr_date)

cr_date is here to store the date when a user was added to a group.

1- Does giix can provide an input for users_groups.cr_date ?

2- For many-many relations, giix generates checkboxes lists, is it easy to replace that with select boxes with multiple choices ?

Thanks !