Set Blacs grid over different MPI groups

[rs_ionela]

Hi,

I'm working on a parallel application (simulation) which requires that some of processors from a MPI communicator do some operations, and others to compute the eigenvalues.
To compute the eigenvalues I'm using the Scalapack PDSYEVD routine.
What I want to do is to split the communicator into a desired number of MPI groups and use the ScaLAPACK routine over a MPI group. But I don't know how to set the Blacs grid over different MPI groups.

Can anyone help me?

Best regards,
Ionela