Parabolic unitals in a family of commutative semifield planes

In the commutative semifield planes constructed in Zhou and Pott (2013), we obtain a family of parabolic transitive unitals. For any unital in this family, we prove that there is a collineation group fixing it and acts sharply transitively on its affine points. We also consider its dual unital, the collinearity of its feet and show that as a design it is always resolvable. In particular, we give a necessary and sufficient condition under which a unital in our family is equivalent to a Ganley unital derived from a unitary polarity.