Concatenate a Range based on cell values

Given Out put desired (Using Formula)
ADDKRT
KRTADD
Round Trip ADDKRTADD
ADDJNB
JNBDAR
DARADD
Round Trip ADDJNBDARADD
ADDHKG
HKGMAAADD
Round Trip ADDHKGMAAADD
-
HKGMAAADD
Round Trip HKGMAAADD
ADDCAIBRU
BRUDXBHKG
HKGMAAADD
Round Trip ADDCAIBRUDXBHKGMAAADD
ADDCAILGG
LGGLUXPNR
PNRADD
Round Trip ADDCAILGGLUXPNRADD
ADDCAILGG
LGGBRUDXB
DXBHKG
HKGMAAADD
Round Trip ADDCAILGGBRUDXBHKGMAAADD
ADDLGG
LGGLOS
LOSLGG
LGGACCLOSLGG
LGGADD
Round Trip ADDLGGLOSLGGACCLOSLGGADD


Description of what i have {left side above} and what i am trying to do {right side above}
left side above are place (sectors e.g the first one is Addis Ababa-Khartoum & Khartoum-Addis Ababa) and immediately followed by "Round Trip". and what i need to get is, as shown on the right side above to concatenate the cells between the two consecutive "Round Trips" starting from above and leaving the left most three characters except the first sector.

use this on the first round trip cell and copy and paste as needed.. You will have to adjust the formumla depending on how many cells you are trying to merge, but the last cell should always be the one without the LEFT(C#,LEN(C#)-3 in it (hence just the A3 at the end).





=CONCATENATE(LEFT(A2,LEN(A2)-3),A3)