When you say the house pressure pump “draws” from the underground tank, I assume you have an above the ground pump like a jet pump. Yes this pump can probably also handle your irrigation. Figure out the size of pump and how many GPM it pumps at say 40 PSI, if that is what you want on your sprinklers. Then you need to carefully engineer your sprinkler system to exactly match the output of the pump. If it is a 15 GPM pump, then every sprinkler zones needs to be exactly 15 GPM. Then carefully program it to only irrigate during off hours when you would not be needing water for the house, because there won’t be any pressure left.
Or you can use something like a Cycle Stop Valve before the tank and tee to the irrigation. This way you can irrigate at any flow rate you want, as long as you don’t run more at one time than the pump can keep up with. The CSV will also allow you to set your irrigation zones for less than the pump can produce, so you would still have water in the house even when the irrigation is running. If it is a 15 GPM pump, use sprinkler zones of 10 GPM or less, and you will always have 5 GPM left for the house. In this way you can match your sprinkler system to the yard, not the pump. The trade off here is that you will be paying a little more for electricity by irrigating at 10 GPM if your pump will do 15 GPM. It might cost you 10% more at the most, which would make a $30.00 electric bill go up to $33.00. The convenience and peace of mind of being able to use the water anyway you want, and have constant pressure to boot, makes it more than worth it.