There are two main parties in an Indemnity Agreement, but there can be more than one of each.
Indemnitee: The indemnitee, which may be either an individual or a corporation, is the party that requires protection. This means that they are the party whose liability will be removed with the agreement.
You may only have multiple indemnitees if they are acting together, such as a husband and wife.
Indemnifier: An indemnifier in a hold harmless agreement, which may also be an individual or corporation, is the party who is providing protection. This means that they are removing liability from the indemnitee.
When there are two or more indemnifiers they are held jointly liable for any claims.
For example, if a business was holding a community event on private property, the owners of the property would not want to be held responsible for any injuries, accidents, or other claims in relation to the event. That would make the property owner the indemnitee, and the company running the event the indemnifier.
Essentially, the company would agree to take responsibility for any injuries or harm that arose during the event on private property as opposed to the property owners.