They call themselves the Shrewsbury Primary Care Network Trekkers and will be taking part in Trek26 in London on May 28.
The fundraising walk will see them covering a marathon distance of 26.2 miles.
Mother-of-one Tracy Willocks, practice manager at Prescott Surgery in Baschurch, from Telford, will be joined by Kim Richards, from The Beeches Practice in Baston Hill, Annie Hill, from Pontesbury and Worthen Practice, and Mary Herbert, from Knockin.
Caroline Brown, from South Hermitage Practice, has been nominated as team captain as she came up with the idea of taking part in the walk.
Tracy said: "The walking marathon is organised by Trek26 and the idea of taking part was proposed to Kim Richards by our lead Primary Care Network manager Caroline Brown.
"We then also all joined in and signed up for the event.
"Our training started in February with four-mile walks every Wednesday after work and meeting in The Quarry, which we continue to do.
"We have increased our distance to six miles every Wednesday and complete a long walk every weekend.
"These started at Lake Vrunwy and we have built on this each week, starting at a different GP practice each week.
"We are currently up to 18.5 miles and our walks take in some of the beautiful Shropshire countryside.
"During our training walks we have learned about the different areas that some of us have never visited.
"May is the month of Dementia Awareness Week and we feel this is very appropriate that we are taking part in the walk at the end of the month.
"We each set ourselves the target of raising £300 each and we have exceeded this and just hope to raise as much as possible as anything else will be a bonus.
"Anyone wanting to donate sponsorship funds can do so via our justgiving page for Shrewsbury PCN Trekkers."
People can support the group at https://www.justgiving.com/team/ShrewsburyPCNTrekkers