Copy values from one location to another

Dear all,

is there a way to safely (read: not depending on parallelization) copy a set of values and impose them at another location of the lattice? I would like to do something like

// palabos-style pseudocode
Box3D reg1(10,15,10,15,10,15);
Box3D reg2(20,25,10,15,10,15);
MultiScalarField3D rho = *computeDensity(lattice,reg1);
MultiTensorField3D u = computeVelocity(lattice,reg1);
magic */

Of course I could just write a loop, but that would not work in arbitrary parallelizations.

Thanks for any help