This code system http://hl7.org/fhir/action-selection-behavior defines the following codes:

Code Display Definition
any Any Any number of the actions in the group may be chosen, from zero to all.
all All All the actions in the group must be selected as a single unit.
all-or-none All Or None All the actions in the group are meant to be chosen as a single unit: either all must be selected by the end user, or none may be selected.
exactly-one Exactly One The end user must choose one and only one of the selectable actions in the group. The user SHALL NOT choose none of the actions in the group.
at-most-one At Most One The end user may choose zero or at most one of the actions in the group.
one-or-more One Or More The end user must choose a minimum of one, and as many additional as desired.
<status value="draft"/> <experimental value="false"/> <date value="2021-01-05T09:01:24+10:00"/> <publisher value="Clinical Decision Support"/> <contact> <name value="Clinical Decision Support"/> <telecom> <system value="url"/> <value value="http://www.hl7.org/Special/committees/dss"/> </telecom> </contact> <description value="Defines selection behavior of a group."/> <jurisdiction> <coding> <system value="http://unstats.un.org/unsd/methods/m49/m49.htm"/> <code value="001"/> <display value="World"/> </coding> </jurisdiction> <caseSensitive value="true"/> <valueSet value="http://hl7.org/fhir/ValueSet/action-selection-behavior|4.0.1"/> <content value="complete"/> <concept> <code value="any"/> <display value="Any"/> <definition value="Any number of the actions in the group may be chosen, from zero to all."/> </concept> <concept> <code value="all"/> <display value="All"/> <definition value="All the actions in the group must be selected as a single unit."/> </concept> <concept> <code value="all-or-none"/> <display value="All Or None"/> <definition value="All the actions in the group are meant to be chosen as a single unit: either all must be selected by the end user, or none may be selected."/> </concept> <concept> <code value="exactly-one"/> <display value="Exactly One"/> <definition value="The end user must choose one and only one of the selectable actions in the group. The user SHALL NOT choose none of the actions in the group."/> </concept> <concept> <code value="at-most-one"/> <display value="At Most One"/> <definition value="The end user may choose zero or at most one of the actions in the group."/> </concept> <concept> <code value="one-or-more"/> <display value="One Or More"/> <definition value="The end user must choose a minimum of one, and as many additional as desired."/> </concept> </CodeSystem>