Is there a way to create a Business Partner hierarchy, or associate many business partners to a top level BP, in LN? The company I am working for is already using the partner field on the BP for other purposes that wouldn't be compatible with what we need.

The example of what I need is: there are 10 Sold-Tos that we need to link to a single Sold-to for reporting purposes. The 10 are distributors of the one BP. This is solely a reporting relationship but we want the data available so we don't have to manually link data later.

Many thanks in advance.

The detail tab of the BP session tccom4100s000 gives the ability to assign BP's to a parent, that's the standard functionality for achieving your business requirement.

In LN 10.3, There is provision to maintain, view addressess by Business Partner, more specifically concerned to their roles.
Session is addresses by Business Partner(tccom4133m000), Hope this helps:)