Royal in group having meal (6)
I believe the answer is:
brunch
'meal' is the definition.
(brunch is a kind of meal)
'royal in group' is the wordplay.
'royal' becomes 'r' (abbreviation).
'in' means one lot of letters goes inside another.
'group' becomes 'bunch'.
'r' placed inside 'bunch' is 'BRUNCH'.
'having' acts as a link.
(Other definitions for brunch that I've seen before include "Mid-morning meal" , "Two meals in one" , "Late morning repast" , "Late breakfast, or early lunch" , "Late morning meal" .)