Attached Is or Are

Is it attached to or with?

You could also use “attached with” since “with” is used dominantly when referring to “informative context” whereas “attach to” is better used for “physical attachment,” i.e. attaching something physically to something else.

Which group is or are?

Technically it should be ‘a group is..’. This is because a group is a singular entity in the same way as a company and a school and a class is . . But many people will use the plural ‘are’ because they are more comfortable with it.