When you create a template you are requested to choose a contact group, so when you are sending an email or an SMS text it will only show the templates assigned to that group.
You can always change the contact group in the template, click on edit and choose the contact group you want.
SMS Text:
Email:
In case you need the same template for more than one group you can clone your template and choose different groups for them.
SMS Text:
Email:
