As @dicksonsamwel indicates, no there is no way to get the 'other' value added into the original select_multi result. But what you could do is add a calculation that appends the 'other' question's (string) value to the select_multi's (string) value, and use that result everywhere instead of the select_multi. eg
if(${other}='', ${select}, concat(${select},' ',${other}))
note, the ' ' (space) delimiter is critical.
FYI: the proper (and only) way to do what you want is to have Collect (& Enketa, et al) support open selections, discussed here.