Single-cell stock allocations

I am looking for a solution preferably in DAX, or alternatively in M/Power Query.

My dataset consists of a number of investors' stock portfolios. The number of stocks in each portfolio varies across investors (e.g. one may invest in 2 stocks, another in 10), and so do their allocations towards each.

Each portfolio is stated in a single row in a single column (B), in the following format: Stock 1/5%:Stock 2/10%:Stock 3/85%. Of course the stocks have actual names, this is simply an example.

While the number of stocks in a portfolio is variable, the range of stocks investors can choose is fixed and can be categorized as either Europe, U.S., or Asia stocks.

Ultimately, what I want to calculate is the allocation towards each of these 3 regions (e.g. may Investor X have 10% in European stocks, 85% in American, and 5% in Asian). My current solution in Excel is to extract the stock names, lookup their region in a lookup table, and then sum the amounts in each.

However, my formula is not the most straight-forward, and I cannot seem to convert it to DAX, as I am now moving my calculations into PowerPivot. Here is the formula: 

=SUMPRODUCT(TEXT(TRIM(MID(SUBSTITUTE($B4&$G$4:$G$15;"%";REPT(" ";100));FIND($G$4:$G$15;SUBSTITUTE($B4&$G$4:$G$15;"%";REPT(" ";100)))+LEN($G$4:$G$15&"/");100));"0,000;0;0;\0")*($H$4:$H$15="U.S."))/100

Unfortunately I have not been able to attach the sample workbook, but instead I have enclosed an image of the sheet below. Thanks a lot in advance, let me know if you need further.