Allow a custom field to belong to a folder/project instead of a space or account-wide

For single or multi-select custom fields we often want the values to be able to change depending on where the field is used. For example, we use a signage tracker (we are an events company) and one custom field is 'Location'. One project might require 'Ground Floor, Foyer, Main Theatre', whereas another might need 'Room A, Room B, Room C'. 

Because custom fields belong to either a space or to the account, there seems to be no way to realise this without creating multiple 'Location' custom fields. This causes issues of course, because there is no way of knowing which 'Location' field to choose when adding it to an item, and generally proliferating custom fields is just not a very neat solution

Currently we cannot have single or multiple select fields for this reason and so have to use text fields instead, which is less than ideal.

SOLUTION:

Two possible solutions:

1. Allow a custom field to belong to a folder/project instead of a space or account-wide. Also incude the ability to add an 'Admin label' to a custom field so you could have multiple fields with the same label (e.g. 'Location'), but are in fact separate fields with different admin labels (e.g. 'Location - xxxx')
2. When you check 'Allow others to add custom labels', make it so that i) those new options only appear in the current folder , and ii) the drop-down choices are visible in each field.