6th Gen Beethoven is right. The best strategy is to make such nice, considerate people suffer. But what if unlike him you do not have a vice grip handshake of your own?

Here are two options.
You will have to practice them until they became natural and smooth. (They are also difficult to follow from the written account so get someone knowledgeable to show it to you. I like to flatter myself that I invented the first one, so you would have to see me, but it is easy to understand option. The second one is a traditional move both in ju-jitsu and aikido, so go tho your nearest martial art school and enroll!

)
1. with your hand in the grips of the nicce person, do this:
a) grab your own thumb and make a solid fist around it. b) Use the knuckles of the hand gripping the thumb to put pressure on the back of the hand of the nice friend. c) this is done using a movement like the movement one does when accelerating a motorbike.
There are many nervous pressure points in the back of one's hands. You are basically crushing such pressure points with your knuckles. It requires very little strength, and it immediately makes the other person's hand open besides causing excruciating pain as the nerve centres get pressed. At which point you can grip thier hand and not let them go away. I had some big fellow once on his knees crying and begging me to let him go with this one. Since I am not that big or strong, and this particular guy was not very well liked (he was always crusshing people's hands), this caused untold merriment amongst the crowd in the party where it happened.

2. As he grips your hand, rotate your forearm (it is an easy movement requiring no strength and the other person cannot resist it) so that your hand is now palm down and his hand is palm up. Now, grip his hand so that he cannot escape (if he sees what is coming), and move to the outside of his arm. When the handshake started you were facing each other. Now you are at 90 degrees to each other, him facing the original direction, you on his outside, facing his side. In this positions his arm will be awkwardly bent. Now do the next three moves all at the same time:
a) pull your hand (the one in his handshake) up, so that his elbow points up.
b) use the other hand to grab the elbow from above
c) Step forward
d) Bring his elbow down towards you (the elbow will basically follow an upward circle first pointing to the direction you were facing to finally pointing to you.)
If you do this in a slow and controlled way, you will throw him on the floor (the pain in the elbow and shoulder joint will do it for you). If you do it fast and brusquely (again it has nothing to do with strength) you will dislocate his shoulder and tear the elbow ligaments. So decide how much you like this guy and use the appropriate amount of speed/control for the desired results.
This is the move it will be better to have it demonstrated to you. (Watch Steven Seagall movies, he is always coming up with this sort of nice stuff).
On second thoughts you can alwyas headbutt him (or pay someone to do it for you).
After doing this to two or three people, you will get well known and you will be always approached with care and consideration.
Best wishes,
Bernhard.