Inter-subjectivity in Radical Constructivism

In order to combat claims of solipsism, von Glasersfeld must admit an inter-subjective reality. In the video he says, "the inherent difficulty (to adopting RC)... in order to interact with other people, you have to concede an inter-subjective reality, which is not a reality in which things exist in their own right, but a reality in which your ideas become more or less compatible with the ideas of the other person." I understand the position of RC appears useful solely for epistemological purposes, as in what we can and cannot know, and attempts to put aside the possibility of the ontological objective "real" world, in favor of the experiential world, however, conceding an inter-subjective reality seems to admit of an objective reality; the moment one concedes of an experiencing agent other than oneself, how can the experiences be known to be compatible without an objective reality? Solely from experience, can one know that the "other person" does not "exist in their own right"? Perhaps, von G would say that one cannot know one way or the other, but it would indeed be radical to claim that in an inter-subjective reality, the other person may not exist in its own right, when experience of this reality tends to strongly suggest the opposite. If inter-subjectivity is conceded, I can see the practicality of RC, in that, "all communication and all understanding are a matter of interpretive constructions on the part of the experiencing subject". As the constructions vary from subjective agents, and the object of our constructing becomes merely a concept as we experience it, and we cannot know it "in its own right", or even if such a thing "in its own right" exists, what is considered knowledge may need to be reevaluated. However, whether these concepts cohere with reality, or become reality, or not, they seem to work, as, "...ideas become more or less compatible with the ideas of the other person."

Does the conceding of an inter-subjective reality point towards conceding of an objective reality?