inter-group communication vs liaison

inter-group communication and liaison both are nouns.

Word	Noun	Adjective	Verb	Adverb
inter-group communication	Yes	No	No	No
liaison	Yes	No	No	No

As nouns, inter-group communication and liaison are synonyms defined as:

inter-group communication and liaison: a channel for communication between groups

Other synonyms of inter-group communication include contact, link.

inter-group communication (noun)	liaison (noun)
a channel for communication between groups	a channel for communication between groups
	a usually secretive or illicit sexual relationship