The phrase, "were concerned with" can be replaced by a variety of synonyms depending on the context. For example, "focused on" or "prioritized" can convey a similar meaning. "Attended to" or "dealt with" may also be appropriate replacements. "Engaged in" or "involved with" can be used to imply a level of active participation. "Occupied with" or "preoccupied with" can also be used to indicate a strong attention to a particular matter. Whatever the context may be, using synonyms for the phrase "were concerned with" can help to clarify and vary the language used in written or spoken communication.