Linking Template to a Block can be done through package definition XML file via link tag. Link multiple Templates can be done by using as many link tags as needed.

link tag must be presented under the root links tag as following:

<object type="block">
  <links>
   <link name="TEMPLATE_NAME_1" />
   <link name="TEMPLATE_NAME_2" />
   <link name="TEMPLATE_NAME_3" />
  </links>
</object>