Can you? Yes, You can do anything you want. Should you? No and I`m not sure why you would. If your PCP 100mg and they won`t raise it then scrap it and just go through the clinic. Don`t stack the two. That`s going to cause all sorts of confusion when both medical providers do labs. That also means you are going to have to supply labs for both of them. Both are going to want you in X range so if you stack them they are going to see your numbers are to high and reduce your dosages.
As far as they (the doctors) are concerned they are going to look at your labs and put you where they want you. You might get a TRT clinic that will do adjustments based on how you feel but it just depends on the clinic and they are going to cap you out at X dosage even if you don`t feel the way you want to fill.
What is your total and free test levels on this 100mg per wk? What is your estrogen?