How to sort a 1x1 struct based on the struct in the deep level of the struct?

A is a 1x1 struct. A.EachFrame is also a 1x1 struct. There are 32 1x1 struct inside A.EachFrame:

Item_1

Item_3

Item_5

...

Item_63

Inside each item, it is Position.Item_1.RealPosition(1). RealPosition(1) is a number. Item_1 here is fixed. For outside Item_1, Item_3 to Item_63, RealPosition(1) are different:

73.5

70.5000000000000

67.5000000000000

64.5000000000000

61.5000000000000

58.5000000000000

55.5000000000000

52.5000000000000

49.5000000000000

46.5000000000000

43.5000000000000

40.5000000000000

37.5000000000000

34.5000000000000

31.5000000000000

28.5000000000000

121.500000000000

118.500000000000

115.500000000000

112.500000000000

109.500000000000

106.500000000000

103.500000000000

100.500000000000

97.5000000000000

94.5000000000000

91.5000000000000

88.5000000000000

85.5000000000000

82.5000000000000

79.5000000000000

76.5000000000000

I want to sort Outside Item_1, Item_3 to Item_63, according to RealPosition(1) value, from low to high (or high to low). The expected result should be the first item is the one with the lowest RealPosition(1) value, in this case, Item_31, with RealPosition(1)=28.5.

I exacted all RealPosition(1) to an 1D array pos_array. I tried to use

snew = orderfields(A.EachFrame, round(pos_array));

It didn't work because A.EachFrame was 1x1 struct but there were 12 elements in pos_array. So how to re-arrange this 1x1 struct based on the value in the deep level of the struct? Many thanks.