Combo chart with target line

Hi community,

I have my sales data set in 2 tables:

Table 1: sale id, date, customer id, supplier id

Table 2: sale id, item id, price, discount, currency

From the above tables i calculate the sales amount and display it on a combo chart month by month. This works well so far.

in a third table i have the yearly targets by month:

Table 3: date, target

FOr each month of 2019, i have set a target. I want to display those targets month by month on the combo chart displaying sales. Note that the sales and targets tables are not linked. So the expected outcome will be as per the attached image. 

Any help will be much appreciated.