Hoping for some advice or to be pointed to the correct terminology so I can research further.
I have a table of equipment, each of which can have multiple suppliers and also have multiple attachments.
I’m looking for a way to firstly filter by the specific piece of equipment (always one selection) then filter by attachments (typically multiple Selection) which should leave me with only the list of suppliers who can fulfil that requirement.
@Aaron1040 The good news is that what you describe is a fairly common requirement and there is, in fact, an established method for handling it. It is commonly referred to as "Cascading Comboboxes". The "upsteam" control (which is usually a combobox, but could be a listbox) is based on the higher level category. The "downstream" control (again, combo or list box) is based on the lower level category and it is FILTERED by a selection made in the upstream control. The after update event of the upstream control is used to apply that filter to its downstream partner.
Searching on the term cascading combobox should turn up a plenitude of discussions and examples.