can consecutively numbered mesh parts be contiguous

Hello,

I'm using ParMETIS for mesh partitioning in a finite element code. I'm building the dual graph myself and using the ParMETIS_V3_PartKway routine for partitioning the graph.

For N_parts == N_MPIprocs and for N_parts != N_MPIprocs; N_MPIprocs == 1 everything is working fine.

The use case that I need is the following:
* N_MPIprocs = 1 (I can use METIS too, if that library is more appropriate for this)
* N_parts - arbitrary
* N_group < N_parts; N_group % N_parts == 0; such that the first N_group consecutively numbered parts form a contiguous mesh part, the next N_group parts form another contiguous mesh part and so no.

Is this possible with ParMETIS?

I'm adding a diagram, I'm not sure how well I've explained:

12 mesh parts, groups of 4 mesh parts

===================================
|| P0 | P1 || P4 | P5 || P8 | P9 ||
==---------==---------==---------==
|| P2 | P3 || P6 | P7 || P10| P11||
===================================

Groups: P0->P3, P4->P7, P8->P11

Thank you,
Radu Popescu