splunk chart doesn't show all site data

Question

from checkbox value, if i choose multiple sites, i would like to show all sites separate line chart for avgtrackout time. now the problem if i choose multiple sites, it only show one line chart by coming all sites avgtrackout value.

query: MicronSite IN($site$) index=mtparam sourcetype=CommandTimesByArea | rex field=_raw "Fabwide:AvgTotalTrackoutTime\s+(?<AvgTotalTrackoutTime>\d+)" | timechart span=12h avg(AvgTotalTrackoutTime) aligntime=@d+7h avg(command_time)

For example: from check box list i choose "F10N" and "F10W". but in chart, only show one line by combing those two site avgtotaltrackout time values and show one chart. i would like to show separate avgtotal trackout time value for two separate chart

please help to suggest for this issue