Tracking Item in 2 Unit Types

Tracking Item in 2 Unit Types

We sell slabs that are individually measured and billed. Currently, we track inventory on a Square Feet basis. We would like some way of also tracking the number of slabs being sold alongside individual measurements. 

Would it be possible to achieve this using some workaround/custom function/script etc??

The final outcome :
Existing Stock on Hand for Yellow Color - (82 Slabs / 1503 SFT) compared to current 1503 SFT. 
Sales : 8 Slabs of Yello Color measuring AxB - 3 Pieces, AxC - 5 Pieces, total N SFT
Updated Stock : 74 Slabs / 1503-N SFT.