Quartus 12 and SDI Megafunction

I am trying to compile a design that requires 6 SDI Transcievers in an ARRIA V part.

One "six-pack" of transcievers contains a 4 lane PCIe function and the other two "six-packs" of transcievers are needed for the 6 SDI Transcievers.

I can only get 2 transcievers per "six-pack". Depending where I locate the transciever I/O pins, the error message changes. It appears that there is a shortage of clock inputs even when all 6 transcievers are using the same clocks.

Han anyone else encountered this problem. I can fix it by selecting a larger device but the 12 spare transcievers should be sufficient to support 6 SDI transcievers.