Ability to select multiple upstream traces at once

It would be useful to be able to hold ctrl / shift / alt or another keyboard link to be able to visualise multiple upstream traces at once. So after one trace has been selected, we could hold a key down and make another selection and retain all traces on the screen. This is particularly useful when flow survey planning to highlight multiple legs of shower at once to be able to check coverage without the need to go through and create selection lists while planning for each monitor and drag each one onto the geoplan in turn.