Hi Aaron,
of course it can. I should have put it in the example. But the question aims to if there is a \partCombine setting that considers (and prevents) the frequent alternation of "a2" and two voice passages. Something like «If the "a2" passage lasts for less than (so to speak) 5 notes, then use the \partCombineApart option».
Thanks for your answer!
F.