Digee Serum relates to digestive system
Key Pen Serum for Kidney and pancreas.
You can give them separately as they relate to separate healing.
Sir recommends to use max of 5 energies relating to same healing.
You can give PERFECT HEALTH SERUM in any of the health healing.
Also if there are multiple health issues, one can give more frequently MAHAMRITYUNJAY MANTRA energy
Self reading MMM meditation by Sharat Sir can also help