You are very right to work this feature as a global restriction instead of doing it field by field.
Is there any chance this new feature could also help filtering the inline-filters shown to the end user when the shown filters are coming from linked records?
This is great news! Although we would much prefer the mockup solution by @PaulKalvelage (or even a combination of global and local), this could be incredibly useful. We have spent countless hours trying to find workarounds only to hit a dead end time and time again.
We will support both eventually 
Right now we’re exploring 1) global restrictions based on user’s record ownership → This extends to not just dropdown but also inline filter, conditional filter on each block. It’s the most critical for any portal use cases.
Something similar @PaulKalvelage’s solution will also be needed → This 2) local filter can filter data based on other variables, such as:
I have at least two big projects that are blocked by this limit. An implementation like this could lead to a “boom” in the use of Softr in numerous contexts! We are waiting! 
We are also being blocked on a project because of this
I see “Dynamically filtered dropdown options” on the roadmap. Is that what you are referring to?
Do you have any idea on timing for that? (It is currently in the “Under Consideration” bucket. The workaround will work but it means that I have to do set up an AirTable View and block for each client. Which is manual, error prone, and hard to maintain.
Hi Softrs - just adding my need for similar functionality. In case it’s useful, here’s the use case:
AirTable: Items table, Sizes table and Orders table
Softr: Table block with action button to Add Order (i.e. a specific quantity of a specific Item in a specific size. Items are only available in certain sizes, and these are stored in a linked record in the Items table. So the Items table links to the Sizes table to store what size an item can be ordered in. The Orders table links to the Sizes table to store what size an order was placed in.
Hi all,
Exciting update: the “Global Restrictions” feature is live and it’s a hit! I’ve just set up user-specific dropdowns with ease, thanks to this new addition. I hope it works for you as well.
Big thanks to everyone who made this possible.
Cheers
“SYNC OPTIONS WITH DATA SOURCE” is also compatible with linked record fields?
Yes 