No, it is not okay for a girlfriend (or anyone) to call her boyfriend's other girlfriends and tell them to stay away. This behavior is possessive, controlling, and disrespectful to both the other girlfriends and the boyfriend. Relationships should be built on trust, communication, and mutual respect.
If someone is feeling insecure or uncomfortable about their partner's relationships with others, it is important to address these feelings openly and honestly with their partner. Effective communication is key to resolving any concerns or insecurities in a relationship.
Attempting to control or manipulate the other people involved is not a healthy or constructive approach. It can lead to negative consequences and damage trust between all parties involved. Instead, it is essential to have open discussions and establish clear boundaries within the relationship, allowing everyone involved to make their own choices and decisions. If the situation becomes too challenging, seeking the guidance of a professional therapist or counselor can also be beneficial to address underlying issues.