@Override
	public boolean isValidIndex( long index ) {
		for ( int i = 0 ; i < programs.length ; ++i ) {
			try {
				Address indexAddress = baseAddresses[ i ].add( index );
				return programs[ i ].getMemory( ).contains( indexAddress );
			}
			catch (AddressOutOfBoundsException e) {
			}
		}
		return false;
	}
TODO
Check to make sure programs are disjoint and contiguous memory spaces.
Ghidra/Features/FileFormats/src/main/java/ghidra/file/formats/ext4/MultiProgramMemoryByteProvider.java