Gst billing - different serial no's

Dear Sir,

I am a labour contractor and registered GST Dealer In Delhi, We are dployed labour in various State for construction work with different Builders. My question is - in Delhi we can maintain separate Bill No's for every construction Site ? 

For Example - Bhiwadi - Bill No. B1, B2, B3, B4

                        Noida - Bill No. N1, N2, N3, N4

                        Chandigarh - Bill No. C1, C2, C3, C4

This is a right process to maintain Sales Register, Please advise -----