Through 12/17, the following are the records of each of the P6 hoops conferences against the other five.

B12...17-11....61%
ACC...27-18....60%
EAS...19-17....53%
PAC...14-15....48%
SEC...15-21....42%
B1G...19-29....40%

There is a significant disparity between the number of such games per conference member. The Big East has played the most, and the PAC the least.

EAS...3.6 games per member
B1G...3.4
ACC...3.0
B12...2.8
SEC...2.6
PAC...2.4

18 P6 teams have not yet won an OOC game against a P6. Six of those haven't won because they have not yet played a single P6 opponent. They are:

TCU
California
Washington St
Auburn
Mississippi St
South Carolina

The others are:

DePaul.........0-5
Wisconsin.....0-5
Vanderbilt.....0-5
Stanford.......0-3
Boston Coll...0-3
Pittsburgh.....0-3
Alabama.......0-2
Iowa............0-2
Ole Miss.......0-2
Georgetown..0-1
Colorado......0-1
Oregon St....0-1