Comparing two point hypotheses over brm model

I have a very general question about using the hypothesis() function or other Bayes Factor functions to compare two point hypotheses with regard to a brm model. Say I have

y ~ a + x + x : a

and two somewhat complex hypotheses, both of which contain point estimates:

hypothesis 1 is that a > 0 & x:a = 0
hypothesis 2 is that a > 0 & x:a - .5 * Intercept = 0

is it possible to use hypothesis() to obtain a Bayes factor for h1/h2? Is it possible at all? How might one go about it?

Thank you for any pointers you might have.