No. All common indicators should cover all persons supported under the investment priority that fulfil the relevant definitions. The common output indicator "above 54 years of age" should therefore cover all supported persons who are above 54 years old irrespective of their employment status. Selective reporting is not permissible.
If you need to monitor the specific target group more closely, then the common output indicator “above 54 years of age who are unemployed, including long-term unemployed, or inactive not in education or training indicator” will exclude those (aged over 54) who are employed. If this is still not precise enough for effective monitoring of the specific target group then you could establish a programme-specific output indicator for participants who are "above 54 years of age and unemployed ".
Note that such a programme-specific indicator would not require the collection of additional data; it could be generated by cross-tabulating the data from the relevant common indicators ("unemployed, including LTU" and "above 54 years").