Are you sure its 220 and not two 110 busses. If the ac's are 110, they probably are run off two busses in a junction box. Carefully measure each buss to neutral to determine if this is the case. If it is, the simplist way will be to connect the two buss bars and neutral, plus ground, to a four wire standard 50 Amp cord to plug into the park 50A socket. The generator output should first be removed from the busses and connected to a 50A socket. The 50A cord can then be plugged into either the park output or the generator output depending on the current source of power.
IF YOU DON'T UNDERSTAND ANY PART OF THE ABOVE, PLEASE HIRE AN ELECTRICIAN!!
Ernie