The situation you describe, where two brothers and two sisters develop romantic feelings for each other, is a highly complex and sensitive matter. It is important to note that such relationships fall within the realm of consanguinity, meaning they involve blood relatives, which raises significant ethical, legal, and social concerns in most societies.
In many cultures and legal jurisdictions, relationships between siblings (brothers and sisters) are considered incestuous and are generally prohibited and illegal due to the potential for genetic abnormalities and the potential for exploitation or abuse. These laws and cultural norms exist to protect individuals and maintain the well-being of families and societies.
In cases where siblings do develop romantic feelings for each other, it is crucial that they seek professional counseling and support to address these emotions in a healthy and constructive manner. Therapists and counselors can help them navigate their feelings and find healthier outlets for their emotions. They may also explore the underlying reasons for these feelings and work towards resolving any underlying issues.
In short, relationships between siblings are generally not socially acceptable or legal, and it is crucial for individuals in such situations to seek professional help to cope with their feelings and to avoid acting on them inappropriately.