You will need to network like crazy and bring together songwriters, lyricists, musicians and producers so that they may create world class songs for you to "shop" to labels, radio and television, movies, restaurants, malls, elevators and so on.
Your job would be to place your teams songs with famous artists. You would retain a share of the publishing (anywhere from 15-30%) and the songwriters would share the rest.
There are lots of very talented songwriters and producers who can (if put in the same room) create world class songs. But, very few musicians can get their songs placed with record labels because it is a very crowded and tough market place.
One solution available to musicians is to use the online song submission platform, Audio Rokit to get their songs listened to by top industry reps. You can use this service also to help place your dream team songs with record labels, but as a publisher you will need to go one step further and build personal relationships with industry insiders because it will be your job to guide your writing team. Your team will look to you for advice on what style of music they should work on and who you are likely to place the songs with.
Effectively you become a sort of manager and group leader in return for a share of future profits. Working in this way minimizes your financial risks and maximizes your music industry connections. Try calling a record label and say you are are a songwriter, you won't get far. On the other hand, if you call a record label and say you own a publishing company you at least stand a chance of getting a meeting with them!