Deriving multiple local accounts for a single asset category combination

Summary:

We have a requirement to derive multiple local accounts from a single asset category flexfield combination. For one of my former UK clients we had a major, minor and STAT class category and set up account rules with mapping sets to derive the movement segment. I would have to test this again for my current client but believe this requirement is feasible with a custom SLA rule.

However, when I setup the mapping set, I am receiving the following error:

The input source Category Flexfield Segment 1 has no associated value set defined. Do you want to continue using value set AC0_FA_CAT1 for this input source?