Are you looking for agencies to contact? Go to the Reviews tab.
Select Advanced Search.
Fill in Location (Philly? Pittsburgh?) and the "within" range: 15 miles - 200 miles.
In the "Service Information" section, there is an "Agency/driver/independent" drop down menu.  
Select "Agency"
Hit the "Search" button.
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You should get a list of recent reviews for Providers with Agency affiliations and that will lead you to the contact info (website and / or phone or email) for those agencies.  
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YOU MIGHT NEED VIP FOR SOME OF THE SEARCH FIELDS, but I don't know which ones.  
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Search the Phila Ad board for agencies posting there (XO?).
Search the Pitt Ad board for agencies posting there (XO?).
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Search non-TER websites in your area and try to ID which are agencies and which are indies.
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Good luck!