Yes, there is no problem in doing so, as one feels comfortable.
Most Thai peoples wear amulets in odd numbers such as one, three, and five and so on. Most amulets can be combined freely with no risk of their effects negating each other or creating trouble for the wearer.
It is not necessary to wear amulet with odd number on the the neck. This is for balance purpose, but not necessary.
For example, if you are wearing two different types of Phra Khun Pean from two different temples, there will be no problem of conflicts in energy for this combination. The protective effect of an amulet will not negate the effect of a Metta
(loving Kindness) amulet.
Based on legendary, Phra Khun Paen and Khun Chang are
considered as mortal enemy to each other with their passionate courtship.
So we avoid not to wear them together at the same time.
Phra Khun Paen