You’d have to change the default BP implementation in the template and then either use the second player as a secondary attachment or run it with physics grips so they both apply forces instead of direct following.
(cut out the Already gripping check and drop logic, late updates would HAVE to be off, likely would want to turn off the defaulted center of mass setting as well)
Anything beyond that is up to you as there is no way of me knowing how you would want that to behave.
I have plans to setup something like this anyway eventually using gameplay tags to define an object as multigrippable, but its not a high priority.
There is also a lot of considerations to take into account with multiple players gripping, what behavior exactly are you trying to get?