# Entity Relationships: Party Lists

In Dynamics CRM, a Party List is used to allow a single field to refer to multiple entities. Examples of the Party List type are:

- email.to, email.cc
- appointment.requiredattendees, appointment.optionalattendees

A Party List may include different types of entities in the same list - for example, email.to may have both contacts and system users as recipients of the email.

To map to a Party List, create a semicolon separated string of values in the same format as used for Lookups:

- ID::entityname; ID::entityname

For example:

- 6485c8c6-5758-de11-b8fe-001e0b4641ec::account; 1235c8c6-5758-de11-b8fe-001e0b4641ec::systemuser