You’ll need to put an SLink card in the SQ and run separate cables to the Qu & AB168. Then use the tielines in the SQ to patch the AB to the Qu. You’ll also need set the SQ to be clocked from the Qu.
Since you can transmit 40 channels from the SQ to the QU and 60 channels from the QU to the SQ, the number of in- and outputs of 2 AB168s should not be a problem.