If you need to enter information about an item that you don't fully own into BusinessMind, you can do so, but you should observe the following best practices in such cases.
What cost should I enter?
When supplying the cost of the item, you should put only the portion of the cost that is yours. For example, if you partially own an item which costs $180,000 in partnership with another entity or entities and you own 40%, then the cost you should enter in BusinessMind is $72,000 ($180,000 X 40%).
Should I record the unowned value of the item somewhere?
Yes. Define a custom field in your SKU screen, perhaps called non-asset-cost , and list the unowned portion of the cost of the item there. Optionally, also record the names of the other owners of the item, either in the notes, or, in additional custom fields, labeled as desired.
Everything else about the item can be recorded normally. Your inventory value will correctly reflect only the portion of the item that is your asset. If you sell the item, that should be recorded normally too. The profit may appear exaggerated, but this will be offset when the item's partners bill you for their share of the profit.