Value can only be assigned to one item per category in a table (Radio button-like use case without using Radio buttons)

Question

I have a table with a list of items & various columns.

One of the columns is Type, of which the possible values are A, B, C etc...

The user is able to assign a binary value Is X?=YES or NO via a dropdown.
At any one time, only a single item per Type can have Is X?=YES (functionally, its like a radio button)

If the value of item Owl is NO and the user sets it to YES, it will remove the existing YES from item Ape and automatically assign it as NO

An example of such a table is below. As you can see, only one item in each Type A & B can have the value of Is X?=YES

Name	Type	some_value1	some_value2	Is X?
Ape	A	1535	7462	YES 🔽
Owl	A	2	11	NO 🔽
Bear	A	76	2251	NO 🔽
Crab	A	8133	754	NO 🔽
Apple	B	743	1245	NO 🔽
Pear	B	99	2436	YES 🔽
Grape	B	743	1244	NO 🔽

How do I convey to the user that only one item per Type can have the value of Is X? set to YES?

I did not use radio buttons because the user might think they can only choose one item from the whole table.
Whereas in this case, its possible to choose 2 or more (as long as they are of different Type)

Feel free to suggest a totally new way of doing the UX if you think its clearer.

Answer 1

Try baking the constraint into the table header, and have an interaction when a user changes the 'X' per type.

I don't know how frequent a user will be configuring this, so you could use the table header to explain the constraints (the what); if more explanation is needed, use the info tooltip to tell them the why.

You can pair that with some feedback. When they select the dropdown to YES, a label appears, telling them what type this is the X for. This way the column sort can show them the YES's in a row, plus labels for each type represented, which is helpful if you have a decent amount of types.

Scenario: each type must have an x before proceeding

If selecting an X for every type is mandatory, you can pop a warning message above the table that tells them they must select an X for Type C.

Testing: try a version with proximity for Type and X

If you have many columns, one thing you can try is to place the related columns next to each other, to cut down on the scanning.

Answer 2

The user is able to assign a binary value Is X?=YES or NO via a dropdown.

Just replace captions for dropdown items:

• 'YES for Type A' instead of 'YES'
• empty item instead of 'NO'

This make column more readable and eliminate visual noise of repeated 'NO' captions.

Is it possible not to have any YES for particular type? If one YES for each type is mandatory your dropdown may contain only one item with YES value.