It cannot be disabled.
Proper design and ip planning with summary advertisements should however help in reducing the occurence of SIA
There was an eigrp enhancement proposed (EIGRP SIA rewrite) which does not delete the neighbor rather sends out an SIA query at half the active timer. If it receives an acknowledgement to this, the neighbor relationship stays up. I am not sure whether this is available in the new codes
HTH
Narayan
