USA
9 Parties Required
There must be at least two parties to a contract, a promisor and a promisee, but there may be any greater number.
10 Multiple Promisors and Promisees of the Same Performance
1. Where there are more promisors than one in a contract, some or all of them may promise the same performance, whether or not there are also promises of separate performances.
2. Where there are more promisees than one in a contract, a promise may be made to some or all of them as a unit, whether or not the same or another performance is separately promised to one or more of them.
11 When a Person May Be Both Promisor and Promisee
A contract may be formed between two or more persons acting as a unit and one or more but fewer than all of these persons, acting either singly or with other persons.
163 When a Misrepresentation Prevents Formation of a Contract see also Validity
If a misrepresentation as to the character or essential terms of a proposed contract induces conduct that appears to be a manifestation of assent by one who neither knows nor has reasonable opportunity to know of the character or essential terms of the proposed contract, his conduct is not effective as a manifestation of assent.

