Multi-channel (i.e. 4+) buffer~, play~, and groove~???

Has anybody come across (or made) a [buffer~]-like object which
accommodates more than four channels? And/or playback objects to
match? I need it to work with eight for my current project (though
more would be useful for future reference).

Of course, if I could choose which of the source channels to load
into a normal [buffer~] (e.g. 1, 2, 3, 4 into one and 5, 6, 7, 8 into
another), that would work fine -- I can sync the output using
[play~], for example. But I'm pretty sure (from my explorations at
least) that that's not possible. Can anyone suggest a workaround?

I'd be very grateful for thoughts. Many thanks.

pete.