Yes it can be done.
Catch 1st horse. Unrug. Curry and brush saddle area. Put saddle cloth and saddle on with a loose girth. The horse’s back is now warming up to the saddle.
Pick out hooves. Each time you go past the girth do it up a hole or 2.
It is quicker if you don’t boot or bandage. If you do - boots are quicker. Remove mud and put boots on.
Put bridle on.
By the time you have walked to the mounting block, your horse’s back is warm and your girth is tight.
One lap of long and low in walk. One lap of walk. Then go down the centre line asking for shoulder in. If you are pressed for time you only have to do a few steps of all the lateral work, not the whole arena. Change rein with a tear drop to the centre line, go down centre line and shoulder in on the other rein.
Tear drop to centre line and travers. Tear drop to centre line and travers on the other rein.
Tear drop and half pass. Tear drop and half pass on the other rein.
You are now warm enough to trot, in Australia anyway!
Repeat in trot. You can do a few circles if you wish, you can also leave them out if no time.
Repeat in canter.
Free walk on a loose rein back to untack.
Have brush with water. Brush where sweating. Sweat scraper only using the rubber on the bony leg bits. Use the back of the scraper on most of the horse. You should hear the water hitting the ground. Rug. You can put a rug on a wet horse. The rug must always be dry. Put away.
Catch next horse. If they are a long way away then yes catch both horses at the same time and leave them tied while you ride.
This is where my signature comes in. Study it. It is very true and the secret to riding horses. You don’t have to ride to the 20 minute mark.