Start & End of the data series

[0-0 Wai Wai ^-^]

Is it possible to do the following:

When I paste this formula beside the data series, it detects:
- the upper & leftmost cell as the start of the data series.
- the lower & rightmost cell as the end of the data series.

Eg:
There are 2 data series, separated by empty cells:
First data series: A1 to C5
Second data series: E2 to J7

When I paste the formula beside the data series, it will detect automatically.
=sum(detect_data_range)
=sum(A1:C5)

=sum(detect_data_range)
=sum(E2:J7)

Thank you!