+---+ +---+
| 3 |----------------| 6 |
+---+ +---+
/ | \ / |
/ | \ D / |
/ | \ / |
/ | \ / |
/ | \ / |
+---+ | +---+ |
| 1 | A | B | 4 | E `|
+---+ | +---+ |
\ | / \ |
\ | / \ |
\ | / \ |
\ | / C \ |
\ | / \ |
\ | / \ |
+---+ +---+
| 2 |---------------| 5 |
+---+ +---+

The diagram above represents the layout of a new prison.

- There are 21 guards, 45 prisoners, six towers for the guards and five compounds for the prisoners.
- The towers are numbered from 1 to 6 and the compounds lettered A to E.
- All of the compounds are triangular in shape and have a guard tower in each of the three corners.
- The number of prisoners in a compound is equal to the total number of guards in the towers on the corners of the compound.
- There are 11 prisoners in compound A, one guard in tower number 2, four guards in tower number 3.
- At least one guard must be in each tower.
- No two towers contain the same number of guards.
- No two compounds contain the same number of prisoners.

Based on the clues given above, determine the number of guards in each of the six towers?