Absolutely no problem. We frequently do something like this using BWI to go out the lower midwest (generally WN destinations with the low fares matched by all the airlines) on CO and our routings frequently look something like this:

Ticket #1: EWR-DCA-EWR
Ticket #2: BWI-CLE-SDF-EWR-BWI
Ticket #3: BWI-CLE-BWI
The flights are taken in this order:
1 - EWR-DCA
2 - BWI-CLE-SDF
3 - SDF-EWR-BWI
4 - BWI-CLE
5 - CLE-BWI
6 - DCA-EWR

Tickets #2 and #3 are CO tickets nested within the EWR-DCA RT and the stop at EWR on the 3rd leg is simply a transit point with no consequences to the ticketing scheme.

[This message has been edited by monitor (edited 01-11-2001).]

[This message has been edited by monitor (edited 01-11-2001).]