Walking the Dogs: Solution

It can certainly be done. Identifying the fifteen dogs as A to O, here is one such arrangement:

Monday

Tuesday

Wednesday

Thursday

Friday

Saturday

Sunday

A-F-K

A-B-E

B-C-F

E-F-I

C-E-K

E-G-M

K-M-D

B-G-L

C-D-G

D-E-H

G-H-K

D-F-L

F-H-N

L-N-E

C-H-M

H-I-L

I-J-M

L-M-A

G-I-O

I-K-B

O-B-H

D-I-N

J-K-N

K-L-O

N-O-C

H-J-A

J-L-C

A-C-I

E-J-O

M-O-F

N-A-G

B-D-J

M-N-B

O-A-D

F-G-J