Psykers and Inquisitors?

In a game today, an 'interesting' rules conundrum cropped up - I have 4 psykers in a warband that want to use their barrage. There is an inquisitor in the warband - do I use the psykers Ld or the Inquisitors?

The way we rolled it was that they use their own, but I'm uncertain for the future of the unit?

"A psychic test is a leadership test, however, where Leadership tests could be taken on the value of another model, aPpsychic test is always taken on the Psyker's own leadership" pg 67 of the BRB