I don't think you can compare a "white avengers" to a "black avengers." Say you have 100 characters, 90 of which are white, 10 of which are minority. There is obviously a good chance that all characters are white, not through choice of skin color but by the numbers.
and out of those "10" how many know each other, live in the same areas and/or worked with one another at some point.
Avengers:
Falcon
Luke Cage
Monica Rambeau
Triatholon
Rage (never a full member)
Black Panther
Heroes for Hire:
Luke Cage
Misty Knight
New Warriors:
Night Thrasher
Silhouette
Bandit
Rage
Aegis
Debrii
The Crew:
Kasper Cole
Rhodey
Josiah X
Harlem Connection:
Luke Cage, Falcon, Debrii (maybe), Kasper Cole
New Orleans Connection:
Monica Rambeau, Brother Voodoo
Non-Superhero Team Comic Book Team up:
Black Panther, Falcon, Luke Cage, Goliath (kinda)
Black Panther, Brother Voodoo, Blade, Luke Cage
Black Panther, Night Thrasher
Black Panther, Storm
Storm, Misty Knight, Luke Cage
Brother Voodoo, Blade
Falcon, Kasper Cole
Interpersonal relationship:
Brother Voodoo and Blade have worked together on more than one occasion. <---BV and Blade buddy book?

?
Just about everyone has worked with and/or likes Black Panther.
Luke Cage dated Goliath's ex-wife
Bandit and Silhouette were an item (maybe still are).
Misty Knight was Jean Grey's roommate. Storm was Jean Grey's best friend.
Luke Cage and Misty Knight are both good friends of Iron Fist (and maybe dated?)
I could go on.
The point is that a team-up of
3 would be more highly probable that 3 random white heroes due to the fact there are less degrees of separation.