Yes, you could do the same as you are doing with the _mb form.
Assign the Tempvar to Me.LControlsID, and put the same default value for that control on the _hm form.?
As there is no record to match, all you are doing is setting a new record's value to that of the TempVar. if a record existed with that value then you would be shown those records.
I am not saying this is the best way, but it is one way, which you are comfortable with using, especially as you are setting the default value on the destination form.
HTH