Filter a list of tuples in Haskell

Question

I'm pretty new to Haskell and I'm trying to filter a list of tuples that contain a string and a list of strings. I want to filter based on if the list of strings contains a certain string. I'd like to create a list of lists where each list is the first element of every tuple that evaluates to true for the filter.

Example:
Given this list of tuples
progLanguages =
[ ("CptS121" , ["C"]),
("CptS122" , ["C++"]),
("CptS223" , ["C++"]),
("CptS233" , ["Java"]),
("CptS321" , ["C#","Java"]),
("CptS322" , ["Python","JavaScript"]),
("CptS355" , ["Haskell", "Python", "PostScript", "Java"]),
("CptS360" , ["C"]),
("CptS370" , ["Java"]),
("CptS315" , ["Python"]),
("CptS411" , ["C", "C++"]),
("CptS451" , ["Python", "C#", "SQL","Java"]),
("CptS475" , ["Python", "R"])
]

I want to filter the tuples that contain ["Python","C","C++"] and create a list of lists where each sub list is the courses that uses each language.

So, ["Python","C","C++"] would output [ ["CptS322","CptS355","CptS315","CptS451","CptS475"], ["CptS121","CptS360","CptS411"], ["CptS122","CptS223","CptS411"] ]

So far I have the following:

    filter_courses [] courses = []
    filter_courses list [] = []
    filter_courses list courses = map snd (filter ((`elem` courses).fst) list)

This filters progLanguages and outputs a list of all the tuples that use any of the listed languages in 'courses'.

Taking the output from the above list, im trying to do the following...

    filter_more [] langs = []
    filter_more list [] = []
    filter_more list langs = map fst (filter ((`elem` langs).snd) list)

This outputs a list of all the courses that use any of the languages instead of a list of courses for each language.