In theory yes, using IK and constraint objects, in practice results can be somewhat unpredictable, when Constraint objects were introduced (Poser 10 I think) they made a tutorial video about them which made it look easy, however as always they "cheated" using Andy an un-skinned character, on regular skinned characters you tend to get weird breaks.at wrist or knee.

Pre-dating the Constraint objects I made this video https://www.youtube.com/watch?v=-2aoquX_CIk&index=69&list=UUEcKgtoS0Z6ryqTwgcioX9w there's a fairly extensive description of my method on the page, again I think it only worked because I was using the mannequin figure and when I re-opened the file some while later it was an irretrievable mess of doggy chew figures.

For hand shake type motions I think it's best to animate both figures as accurately as possible before engaging IK to hold them together 

Ockham had a script for making  multiple figures follow a leaders actions. Not sure if it's still there (ockhamsbungaow.com)