aligning variables with upbeats

[智樂喬]

I'm sure I'm not the first person to ask this, but I'm looking for a clean, way to align music variables which begin with partial measures. For example,

\version "2.19.82"
partA = { c'2 b | R1*3 }
partB = { \partial 4 g4 | \bar "||"  c'1 }
\score { { \partA \partB } }

In reality, there would be multiple partBs and some of them would start with a pickup and some of them wouldn't. One think I can do is explicitly shorten the end of partA so that partB lines up, but it involves some mixing of content and structure. Is there a best practice for this situation?

Thanks,

Randy