length constraints across components

I'm running 15.5.1 and I need to set up a length constraint acoss a
path that includes active components (ie. I have 2 paths that need to
be matched; each has 2 buffers in it). If I match each section against
the corresponding section in the other path, I get a good length match
but the total length is far from optimal. Is there any way to
constrain the sum of path lengths (like an XNET but for actives)?

Thanks.

/mike

ardai@atb.teradyne.com