<#if condition>
  ...
<#elseif condition2>
  ...
<#elseif condition3>
  ...
...
<#else>
  ...
</#if>

Where:

You can use if, elseif and else directives to conditionally skip a section of the template. The condition-s must evaluate to a boolean value, or else an error will abort template processing. The elseif-s and else-s must occur inside if (that is, between the if start-tag and end-tag). The if can contain any number of elseif-s (including 0) and at the end optionally one else. Examples:

if with 0 elseif and no else:

if with 0 elseif and else:

if with 2 elseif and no else:

if with 3 elseif and else:

To see more about boolean expressions, see: Designer's Guide/Expressions.

You can nest if directives (of course):