I'm also not 100% sure what you're doing, but I'm guessing it's either of 2 options:
1. you're building packages one by one, something like this
poudriere bulk -j 141x64 xorg
poudriere bulk -j 141x64 firefox
This is simple, check out
poudriere-bulk(), especially its "-f" option:
poudriere bulk -j 141x64 -f /usr/local/etc/poudriere.d/packagelist
2. You want two versions of some packages, with different options. Say you want to create jails or FreeBSD VM's that don't have X11 etc as dependencies. In this case you'd build 2 different repositories, but you don't need two jails for this. That's what the "-z <setname>" option is for.
poudriere bulk -j 141x64 -f /usr/local/etc/poudriere.d/packagelist-leanandmean -z server
poudriere bulk -j 141x64 -f /usr/local/etc/poudriere.d/packagelist-alotmore -z desktop
I ommitted e.g. the "-J" option since I don't know your machine and don't want to give out commands that might perform far from optimal. Nonetheless it's a really important one. I would experiment with it, a value I tend to use (on many-core machines with a plenty of RAM) is "-J <physical cores>:<physical cores/2>".
Also sometimes useful: it is possible to run 2 jails (with different -z package-sets) concurrently. I use it when my first bulk build is nearly finished and cores are no longer all in use (e.g. building packages, or non-parallelized builds).
Personal tip note, although I think I'm one of the only people doing this: I name my jails something like "FreeBSD:14:amd64" because then I can use "${ABI}" as a placeholder in my
pkg() repositories. See
pkg.conf() man page for other possible variables. Of course it's also possible to create a symlink, which saves you typing the "FreeBSD:" part when running poudriere.
Also make sure to read the man pages
poudriere.conf() and
make.conf() (make sure you read
poudriere-bulk() so you know the make files it'll (try to) read (hint: it's NOT /etc/make.conf). This will help you achieve better & faster builds on your machine (especially TMPFS=all).