Hospitality to begin with hotel on river (4,5)
I believe the answer is:
open house
'hospitality' is the definition.
(I've seen this before)
'begin with hotel on river' is the wordplay.
'begin' becomes 'open' (both can mean to start).
'with' means one lot of letters go next to another.
'hotel' becomes 'h' (phonetic alphabet: alpha, bravo, charlie etc.).
'on' is a charade indicator (letters next to each other).
'river' becomes 'ouse' (Yorkshire river).
'open'+'h'+'ouse'='OPEN HOUSE'
'to' is the link.
(Other definitions for open house that I've seen before include "Total hospitality" , "Hospitality to all comers at home" , "Place where all visitors are welcome" , "A welcoming place" , "Informal party with hospitality for all comers" .)