Quote from Kamolga on 2019-05-22, 9:51 am

I often want to group people citing a master source (to color or work on them without using static lists).

For example I want to see who use my 'National Archive' master source. For that I create a group 'Sourced_NationalArchive' (with a random person) and use theGroup_MasterSource.sql (below) to update that group.

To update another group 'Sourced_NationalArchive_DeathFact' with people using 'National Archive' master source but in death fact specifically, I use  Group_MasterSource_Fact.sql.

Finally, for another group 'Sourced_NationalArchive_Birth' using the same master source 'National Archive' but only having the word birth used in  reference 

I use Group_MasterSource_Reference.sql to update that group.

There is another method here: http://forums.rootsmagic.com/index.php?/topic/18995-create-group-by-selecting-for-source-title/