Conditional clauses in emails to remove text under a particular condition

I want to create an Email Template in Pupil/Student Manager where two or three siblings can be named in a merge email, rather than having to send two or three separate emails to the same parents:

Dear {{parent.txtlettersalutation}}

I am writing to let you know that Forms and Houses have now been allocated, as follows:

{{pupil.txtprename}} is in Form {{pupil.txtform}}

[insert sibling1 name and sibling1 form but remove line if no sibling1]

[insert sibling2 name and sibling2 form but remove line if no sibling2]

They are in the {{pupil.txtacademichouse}} House

House colours are:

With best wishes.

Please can you let me know (a) if this is possible and (b) what the line should be in terms of {{ }} coding?