Both managers and staff benefit from the workshops designed by a psychological institute to improve relationships within the workplace.
Sync Online has delivered copies of contracts to all the parties who have agreed to participate in a new venture to offer music on the Internet.
In my book's manual, to-infinitive used in 1. (to improve) is adverb, and used in 2. (to offer) is adjective. How to distinguish between adjective and adverb used as to-infinitive like these sentences?