Set Discounted Price if Wallet holds any NFT from certain Collection.

[ChitinNature]

I've been looking to set the final cost of the mint function (and Whitelist) where:

If the connected wallet owns a Founders Pass, an NFT from another collection in which is on same network,
Could I have the code set the value in which holders of that NFT will get an additional discount % off?

I've been trying to use an IF statement after the following condition:

  // Removed mintPriceCompliance as its in the If Statement
  //function mint(uint256 _mintAmount) public payable mintCompliance(_mintAmount) mintPriceCompliance(_mintAmount) {
  //function mint(uint256 _mintAmount) public payable mintCompliance(_mintAmount) {
    require(!paused, 'The contract is paused!');

    address oxTestFounders = 0x3b050c1661fbd802F8Ba06d4aE8E6d9a2C025294;
    if (IERC721(oxTestFounders).balanceOf(_msgSender()) > 0 ) {
            uint256 discountedPrice = (cost * (100 - 20)) / 100;
            require(msg.value == _mintAmount * discountedPrice, "mint: value is not correct to mint that amount - discount");
        } else {
            require(msg.value == _mintAmount * cost, "mint: value is not correct to mint that amount - regular");
        }

    _safeMint(_msgSender(), _mintAmount);
  }

I've been searching to long (about a month) how to do this if its possible. If not I'll just utilize the Whitelist for a couple weeks for the chance of 20% off.

If anyone knows anything and may help. Of course here would be best.
or Twitter @ChitinNature