Custom Pos Solution

Inventory and POS Module to link with Xero. We need a custom Inventory as well as Pos Module, preferably cloud based which must be set up on our hosting. Here are a few requirements Stock will be purchased in foreign currency Purchase Order will be sent to Xero as Account Payables. Each sale will be sent across to Xero either awaiting approval Inventory will be maintained accurately however multiple websites will access this inventory. There must be the option of Negative stock enabled. Inventory is for products at Variant( Matrix Level) For example this inventory would needed to be ordered from multiple suppliers at varying prices. Each product and variant( Eg Style A Size A) will have corresponding supplier codewhich must have some option to customise. Sales from multiple websites will reduce the Stock on the system however the variant is chosen only before sending out the product not at point of sale as we wait for customer to size using a sizer we send, only when size is entered before shipping should the invoice be posted to Xero and based on Min Stock Levels for every variant this will be added to a pending Purchase Order when required. The same product are being sold at different prices n different sites and different currency Please note this is to be created for 4 websites, one running woocommerce, 2 running custom shopping cart ( no api you need to pull from database) one Magento Besides which it need to pull our auction listings from trade me( a site similar to ebay) using their api. The items would be added to a purchase order based on the default supplier( although it can be ordered from other suppliers as well if chosen) The daily sales should be posted individually to Xero in real time as account receivable( pending approval or approved depending on status) At the same time the customer data extracted should be created in Xero as a customer as well with the relevant fields( address phone number etc) The status would be changed to shipped when items despatched and it should automatically create template email to customer with tracking number which is entered. Also the data should be pushed and pulled from Xero example new customer or order created in one should post to the other