I only recently recognised that the values that RootsMagic puts into the Relate1 and Relate2 fields of the PersonTable when the Set Relationships function is applied are more useful than merely codifying the relationship (e.g., see Relationships). Apart from special cases for Self and in-laws, the sum of the two values corresponds to the degree of consanguinity (see this Wikipedia article). For example, the degree of separation in consanguinity is the same from you to your g-g-grandparents (4) as it is to your 1st cousins and your great-aunts and -uncles and your grand-nephews and -nieces. It strikes me that the consanguinity degree might be an interesting, if not useful, basis for color coding. Indeed, it is so easily implemented, I wonder why it is not an option for the Color Code People tool or that consanguinity is not a criterion for finding people and creating groups.
Example of color coding by consanguinity degree. Note that each generation of grandparents gets a different color, a difficult task in RootsMagic.
For the full story and scripts, visit the SQLite Tools For RootsMagic wiki page Color Code by Consanguinity Degree