Screenspace(s) with multiple viewport transforms

hello again,
i have a render transform problem:

i have splitted a renderer in two viewports, each with its individual view and projection transform.
what i am after is adding an object in screenspace of each half renderer and apply individual transforms.
(how) is this possible ?

my context:
multiple renderes in spanmode, individual views and homographies for each half renderer, but then i need also to mask distict parts of individual half renderers.

objects in screenspace and multiple viewport transforms.v4p (13.1 kB)

check the WithinXXXX and Billboard nodes…

i see how the within nodes work with one viewport but i dont understand how to spread the transform of an object across multiple viewports.

would there be another way to crop the viewports ?
in praxis, i want to darken one of the two beamers in the overlapping area (not being interested in softedge atm)

spread transform across viewports.v4p (11.2 kB)

ok, i thought the WithinViewport would do it, its probably a bug… so for now, just do it like this:

spread transform across viewports.v4p (14.0 kB)

i will go for the 2 passes solution … would be nice to have it in one pass tough. thanks