Type seen tailing a small group (6)
I believe the answer is:
assort
'type' is the definition.
(thesaurus)
'tailing a small group' is the wordplay.
'tailing' says to put letters next to each other (to tail can mean to go after or follow).
'small' becomes 's' (abbreviation - e.g. clothes size).
'group' becomes 'sort' ().
'a' put next to 's' is 'as'.
'as'+'sort'='ASSORT'
'seen' is the link.
(Other definitions for assort that I've seen before include "Distribute in classes" , "(Of genes) become distributed among cells" , "Categorize" , "Classify, arrange in groups" , "Categorise" .)