How to Combine Unicode characters in .kcm file for Physical Keyboard on Android?

Question

There are some characters which are not included in Unicode(i.e. श्र which is combination of \u0936 \u094D \u0930) but can be created using combining sequences. I am unable to figure out how to add this for a Physical Keyboard on Android using '.kcm' file.

This is a sample of a generic .kcm file

type OVERLAY

key Q {
    label:                              'Q'
    base:                               'q'
    shift, capslock:                    'Q'
}

key W {
    label:                              'W'
    base:                               'w'
    shift, capslock:                    'W'
}

This is what i want, but its not allowed for some reason

key 5 {
    label:                              '5'
    base:                               '\u096b'
    shift:                              '\u091c\u094d\u091e'
}

key 6 {
    label:                              '6'
    base:                               '\u096c'
    shift:                              '\u0924\u094d\u0930'
    alt+shift:                          '\u0302'
}

How do I achieve/map the above letter श्र, in this format?