High voltage differential amp and CMFB

Attached, I have a pic of the input stage of a high voltage fully differential amplifier (the power supply rails are +/- 100V). There's more to the amp (a single ended VAS stage for each side, output class AB push-pull current buffers), I've just shown the input stage for simplicity. Q1 and Q2 are the inpur pair.

I would like to keep Q3 in the circuit (for a tail current source), and I would like to keep Q5 and Q6 in the circuit (active load for the input stage). I know that the current mirrors must agree with each other (so Iq5 + Iq6 = Iq3). I am planning to bias the stage with ~5mA of tail current (so each half of the input stage gets 2.5mA).

My question is: where should I apply the CMFB input (as taken by R5 and R6, and amplified by the inverting integrator opamp)? I can't seem to get the bias points stable unless I remove Q3 and replace it with a simple resistor. Any suggestions as to what I'm doing wrong?

Thank you!
-Rick

where is the bias of Q5, Q6, and Q7?
if not ,the circuit will not work normally.

Woops! Forgive my error - Q7 is supposed to be diode connected (so that the reference current through it will be mirrored by Q5 and Q6).

Sorry about that...