Attempts to keep it in ridiculously small groups (9)

'small groups' is the definition.
The answer and definition can be both groups as well as being plural nouns.
Maybe there's an association between them I don't understand?

'attempts to keep it in ridiculously' is the wordplay.
'attempts' becomes 'tries' ('try' can be a synonym of 'attempt').
'to keep' is an insertion indicator.
'ridiculously' is an anagram indicator.
'it'+'in'='itin'
'itin' is an anagram of 'niti'.
'tries' placed around 'niti' is 'TRINITIES'.

Can you help me to learn more?