The subject of clans, bloodlines and exogamy has been the cause of immense debate on the Glorantha Digest. Basically, the KoS information should not be taken as 100% reliable, and isn't even self consistent. There were two schools of thought: exogamy means not marrying within your bloodline and exogamy means not marrying within your clan.
A definitive statement in TR is that it is the latter.
YGMV, of course.
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