ISAF 0 requirement and antennas position

I have come across the requirements for offshore racing sailing vessel which are listed here: http://www.sailing.org/specialregs (look at category 0 monohull 3.29.1 B and M and P)

In resume they ask for:

A class A AIS to be installed with the antenna on top of the mast
A VHF radio 25 watt to be installed with the antenna on top of the mast

My understanding is that a minimum of 1.5 meter is required for antenna separation and even if I have that on my boat, I still "hear" my class B transmitting as burst of interference on the VHF radio.

The question is, is there some sort of antenna sharing/splitting that exist for AIS class A that could share the same antenna ? Or is there something that I don't understand in these requirements :think

Northcaptain-
There is no antenna splitter for a class A AIS. It would not meet requirements if attempted. In fact splitters are not even recommended for class B.

I think you need to get some clarification from the ISAF on the requirements of both antenna locations. Maybe they can provide some example of vessels equipped to their requirement.