Nats,
My students receive a list that has all my Usui Reiki lineages. William Rand, and Rick Rivard do the same thing also. However, if you have received complete training in more than one lineage, than theoretically you can give the complete teachings of that lineage and the lineage of your students in that lineage would be the lineage you received in that lineage.
I mean if your teaching Seichim Reiki, your lineage will be your Seichim lineage, not your Gendai Reiki lineage. :-)
In Dharma,
Raven