6/10 found a lot of groups of threes, unfortunately 4 is required. Lots of challenging crossovers...Good solid difficult board

This took a bit of working out but I got there in the end. Thank you for the tricky challenge.

A lot of gaps in my knowledge here, but managed 7/10 with educated guesses.

Same as Urban, lots of threes for me. Couldn't get any groups in the end but identified 3 links afterwards, missing the Tennessee. Cheers for a tough one.

Tremendous grid, well done

You can swap bronco and mustang for valid groups.

Thanks for all the feedback! @Mister Tom - strictly speaking, bronco and mustang are not interchangeable in this instance, as a bronco is any breed of untrained/untamed horse that bucks. Pedantic, I know, but if there's any place for pendantry, it's here :-) :-)

@FirstGofer pedantry aside, it's still a horse. I accept this would make a wider group than the one you intended, but it's still a group.
While what constitutes a valid group is fuzzy - 'noun' being clearly invalid - I personally would not have written this even if i could think of it!

Loves this grid 10/10 - liked the crossovers and appreciate the pedantry