While the Mshikhanim are primarily focused on the gentile followers of Mshikha, it is absolutely open to both Jewish and gentile believers.
The only difference between a gentile Mshikhani and a Jewish Mshikhani is that where the gentile Mshikhani strictly adheres to the Limudah as their covenant, the Jewish Mshikhani observe the Mosaic Covenant.
The obligations on the Jewish Mshikhanim is different from that of the gentile Mshikhanim.
A big problem for gentile disciples is feeling they are required to observe Torah before they are even following the tenets of the Limudah.
Of the two, only one is incumbent on a gentile: The Didache (Limudah). They may gradually, include commandments of the Torah as they are so inclined, but they are not required of them.
The Jewish Mshikhani is called to observe Torah.
The Jewish and gentile disciples should have love for one another, deeply respect one another, even mirror each other in their faith walk. But both should know their respective covenants, what is required of them and not take up obligations that the Father has not called them to, or abandon obligations they have been called to.
The two should be in harmony together, never one trying to absorb the other.